Introduction

The Equator’s linear drive unit is a closed-loop assembly consisting of a drive motor, transmission guide, drive strut, and grating on the rod. If it fails to return to zero, it needs to be separated and checked according to four layers: limit reference point signal, drive body, grating signal, and controller configuration. The discrimination criteria for pre tensioning problems are the single axis bidirectional positioning difference and the platform’s “pushing tolerance”. The expansion and contraction of the three struts were calculated to obtain the platform pose, and the comparison uncertainty was nominal ± 0.002 mm (based on the premise of immediate measurement after re mastering, relative clamping difference between parts and standard parts ≤ 1 mm, and certified standard parts, the X-500 comparison mode was expressed as ± 2 μ m). Any false feedback signal on any layer would render this level meaningless.

1. Original text layer: What exactly constitutes the driving unit

1.1 Two numbers on the component diagram: Drive strut and Drive housing

To read the driver unit, first identify all the numbers on the official component diagram. There are two annotations related to the drive in the Installation and Controller Guide (part numbers 132816300 and 500 share the same set): 6 Drive strut and 11 Drive housing. Accompanying them are 4 Support struts, 8 Upper pivot/Hooke’s joints, 9 Support arms, and 12 Parallel constraint mechanisms.

Three driving struts and several supporting struts are two different types of parts: the length of the driving strut is the amount actively changed by the motor. This must be clearly stated in the disassembly and assembly record – which one was removed from the hand and which number it was, otherwise the subsequent interpretation of the entire record will deviate.

The drive housing is the load-bearing and guiding outer frame of the drive strut. It is connected to the strut, but the official has not disclosed the transmission details, guidance method, and lubrication specifications inside the housing in public documents. Therefore, any judgments related to “what structure is inside the shell” and “how to adjust the guiding surface” fall outside the scope of official disclosure. On site inference can only be made based on external performance and data, and cannot rely on guessing the structure to make decisions.

The strut and parallel constraint mechanism maintain the platform from rotating around its own axis. This explains why the feedback of abnormal pre tensioning of a single strut to the data is often not “how much deviation in this direction”, but “the deviation in multiple directions changes simultaneously and varies with position” – the constraint element redistributes the error according to geometric relationships.

1.2 Three pole linear drive: no lead screw, no belt drive

This one must be excluded first, as it is the most common misjudgment caused by cross industry experience. The Equator consists of three linear drive struts, without lead screws, no belt drive, and no Z-axis column. For maintenance personnel who have switched from machine tools or traditional CMM systems, the diagnostic map of “screw pre tightening back clearance nut synchronous belt tensioning” is completely invalidated here: there is no pitch error, no adjustable reverse clearance nut, and no elastic elongation of the belt.

Instead, a set of linear driving units directly converts electrical energy into linear displacement of the strut, and a grating is installed on the rod for position feedback. The general composition of a linear drive unit can be divided into four sections: power section (converting electrical energy into linear motion), support and guidance section (ensuring motion in a single direction and bearing lateral forces), strut section (transmitting displacement to the platform’s actuator), and feedback section (grating reading head and ruler mounted on the strut). The four stages of failure have different manifestations, and the third section of the investigation is based on these four stages.

1.3 The driving point and feedback point are of the same origin, which is the design premise of the entire machine

Equator’s grating is mounted on the strut, not on the outside of each axis. The core meaning of the official statement is: The driving point and feedback point are of the same origin – the motor pushes this rod, and the grating reads this rod as well.

This results in a short feedback chain close to the execution end, without a reduction mechanism, coupling, or external ruler in the middle for installation bias. The cost is that the feedback chain and the execution chain are physically attached together: looseness, contamination, and changes in the gap between the reading heads on the rod will simultaneously affect both execution and feedback, and the closed loop cannot be detected by itself. The position loop thinks it has arrived, but in reality, the rod may be slightly off, or the reading head may detect a false signal at a certain angle while the closed-loop still accepts it.

This leads to a criterion principle that runs through the entire text: Closed loop self consistency does not equal mechanical correctness. Zero return failure, poor positioning, and lost count all need to be viewed separately from ‘the machine thought it did it’ and ‘the machine actually did it’.

1.4 The counterweight balancing mechanism exists, but it is not publicly disclosed internally

The 7 Counterbalance mechanisms on the component diagram are one of the reasons why the Equator can maintain its motion performance at light machine weights of 25 kg (300 model) and 74 kg (500 model). Officially confirmed its existence, but the internal structure, energy storage method, and regulation method have not been disclosed. Its significance on the maintenance boundary is that it belongs to the component that “knows where it is and doesn’t open”.

1.5 Official publicly available maintainability items are very short

The official public user can only maintain three items on their own: cleaning kit A-5504-9055 (including backup dust filter, prohibited cleaning agent), controller fan filter A-5696-0120 (12 piece set, replacement in high pollution environment after 6 months), and probe inspection. The disassembly and assembly of the drive unit, pre tightening adjustment, and setting of the reading head gap are not included in these three items. This does not mean that on-site inspections cannot be conducted – inspection and adjustment are two separate things: inspection is external observation and data collection, and does not change the mechanical state; Adjustment will change the geometric relationship and fastening state.

1.6 Why ‘can be put back’ doesn’t mean ‘installed correctly’

The three driving struts form a constraint system, not three independent linear axes. Any slight difference in assembly of a strut – due to different tightening sequences resulting in different stress distributions and varying degrees of contact surface cleanliness – will be mapped to the platform pose through constraint relationships, manifested as’ machine movement, incorrect data ‘.

There are four types of controllable variables during the assembly phase: sequence, cleanliness, part number, and fastening status. The sequence refers to the tightening sequence of fasteners and the installation sequence of struts, which must be consistent each time; Cleanliness refers to the absence of particles, oil stains, and residual old media on the mating surface; The part number refers to each strut returning to its original position without mixing; The fastening status refers to whether each fastening point has been reset and whether there are any missing installations. Any one of the four items is ignored, and it is almost impossible to locate them from the data afterwards, because their performance is “occasional, irregular, and multi-directional simultaneous deviation”. This is also the fundamental reason for the existence of disassembly and assembly records.

2. Criterion layer: on-site quantification of pre tightening, back gap, and grating gap

2.1 What is’ pushing open space ‘

The essence of pre tightening is to apply a continuous positive pressure between the mating surfaces, pressing down the small gaps that could have existed, so that the parts can stop at a certain position without external force. After a portion of the pre tension is consumed, the remaining gap becomes measurable under static conditions – this is called ‘open space’.

The on-site actions should be standardized to be reproducible: the machine should be powered off and the driver should be confirmed to have no output (following the safety procedures in the official manual). According to the disposal principle in Article 12 of the baseline, the 300 model can be assisted by two people to judge the tolerance in small sections without stopping. It is not recommended to manually push the 500 and X-500 models, and instead use a controller to jog and compare three-axis data; Do not push or pull while powered on or enabled. Choose a position on the platform that is convenient for applying force, and do four push and pull movements along three mutually angled directions. First, lightly push, then re push. Gently push to see the starting distance, and re push to see the hard stop point. Reading three sentences: It’s not difficult to push forward a short section, but there is room for improvement when pushing forward again to reach the top; If the ball joint cannot be pushed, can be pushed into place immediately, and there is no virtual position, it indicates that the static pre tightening is still in place, but it cannot be judged as intact based on this (the same applies to early deterioration of the ball joint); If the four results are consistent, it is a reproducible mechanical state. If there is inconsistency, it is mostly related to the force application method or platform posture. First fix the force application point and posture, and then redo.

Pushing and pulling must be done in a free state on the platform: if the machine is in a closed-loop enabled state and driven in a holding position, it will feel holding force rather than cooperating, and the conclusion will be completely reversed. This analogy can only determine ‘whether there is’, not’ how much difference ‘.

2.2 How to measure the single axis bidirectional positioning difference

The single axis bidirectional positioning difference measurement is the actual position lag during commutation, which can be achieved in any programming environment: selecting a reference point in the middle of the stroke; Approach from one side at a fixed speed, record the measurement value, repeat 10 times and take the positive mean; Approach the same point from the other side at the same speed and repeat 10 times to take the inverse mean; The difference between the two is the positioning difference; Repeat at positions 25%, 50%, and 75% of the itinerary to see if the difference varies with position.

To control four variables: approximation speed, approximation distance, pause time, and temperature. Different speeds result in different dynamic lags; The residual velocity upon entering the measurement point varies depending on the approach distance; Different pause times result in different thermal and stress relaxation; The thermal state of the ruler and structure varies depending on the temperature. If any one of the four items changes, the two sets of data cannot be compared together.

When is the pre tightening issue and when is the ball joint issue

These two problems are very similar in terms of data and must be separated by four criteria. Table 1 can be directly compared on-site.

Criterion	Pre tightening problem	Ball joint problem
Hand feel	Unidirectional push has a starting clearance, which runs along the axial direction of the strut	The platform as a whole can be slightly pushed, and the direction changes with the point of force application
The variation of bidirectional positioning difference with position	monotonically changes along the stroke of the strut, and the difference between the two ends of the stroke is significantly different	irregularly changes with spatial position, and has no monotonic relationship with the stroke of the strut
Unidirectional repeatability	usually still around the baseline, mainly manifested as mean shift	dispersion expansion (range increase), with the mean basically not drifting
Relationship with platform posture	The time difference value of posture change does not change significantly	The time difference value of posture change changes significantly due to the switching of the direction of force on the hinge point

Add another negative criterion: if the bidirectional positioning difference decreases after maintenance but the unidirectional repeatability does not improve, the main cause is the empty stroke on the preload or transmission side; On the contrary, if the repeatability improvement is limited and the commutation lag is still present, return to the ball joint direction for re examination. If the criteria for two directions are mixed up, it becomes’ pre tightening adjusted, problem still present ‘.

2.4 Grating Reading Head Gap and Pollution: Performance, Inspection, and Cleaning of Restricted Areas

The grating on the pole belongs to optical feedback and is most sensitive to two types of interference: gap deviation from nominal and optical path pollution. Both are sporadic, with the difference in form: pollution gives random loss or jump, the reading suddenly jumps a large grid at a certain point and then jumps back, or directly reports an error; Gap deviation provides position related deviation, with systematic deviation on a small stroke and normal on other strokes. First, check whether the occasional binding is related to the location, whether the binding is biased towards gaps or surface damage, and whether the non binding is biased towards contamination or cable contact.

Check only for external visible range: check for oil stains, dust, and residual cutting fluid between the reading head and the ruler surface; Check whether the bending radius of the cable at both ends of the travel is pulled and whether the joint is loose; Cleaning should only be done according to the specifications of the official cleaning kit A-5504-9055, and cleaning agents are prohibited.

Three rules for cleaning restricted areas: Do not use any solvents, degreasers, alcohol, or compressed air to blow directly onto the optical path (solvents carry away the protective layer of the optical surface and leave residue, while compressed air blows oil mist particles deeper and may also bring out condensed water); Do not use a cloth or cotton swab to wipe the surface of the ruler horizontally (scratches cannot be restored); Do not adjust the installation position of the reading head to ‘try it out’ (the gap and installation angle have been calibrated, and must be re verified and recalibrated if moved). The official has not publicly disclosed the nominal value and allowable deviation of the reading head gap. Any number that says’ how many millimeters should it be ‘is considered fabricated if it does not come from a random file.

Stratification of Four Causes of 2.5 Zeroing Failure

Zeroing failure (unable to find reference point, timeout, incorrect position after zeroing) is most easily treated as’ machine failure ‘. According to the signal link, there are only four layers, and Table 2 provides the discrimination actions for each layer.

Level	Typical performance	Discriminant action	Excluded direction
The first layer limit and reference point signal	stop halfway back to zero, report timeout, and must report after a certain section of travel	manually run at low speed to complete the travel, and check if an error is reported at a fixed position in a certain section; Check for limit and reference point cables, connectors	signal triggering anomalies, unrelated to driving capability
The second layer of the driving body has abnormal noise, shaking, unstable speed, and single axis overcurrent when returning to zero. After power failure, manually push the direction of the strut to feel whether the resistance is uniform; Smooth and pleasant sound at low speed during power on	Abnormal resistance in the power or guidance section
Third layer grating signal	Can return to zero but reports position error, coordinate offset after returning to zero, occasional jump in point position	Check if the error is bound to the position; Perform external cleaning and cable inspection according to 2.4	Feedback link abnormality, closed loop reads false position
Fourth layer controller configuration and software	Must appear after changing controller or software version, or reset parameters have been changed	Check version and configuration items, compare configuration records from the last normal time, restart according to official procedures	Configuration and parameter layer issues, mechanical no abnormalities

The significance of layering lies in the fixed order: moving down from the first layer, excluding each layer before moving on to the next layer. Skipping the first layer and directly suspecting the grating is the most common resource waste on site – limit signal problems are treated as grating problems, cleaned three times, replaced cables, and the fault persists.

Another fact that must be recorded is that the error message is in two paragraphs, including the error type and detection failure; And ‘clearing all errors’ is a reset, not a repair. Resetting first and then returning to zero, and leaving once successful, is equivalent to discarding a valuable fault record.

Three time criteria outside the 2.6 criteria table

In addition to spatial and state criteria, there are three criteria related to time. The first point is whether the fault is related to the preheating time. Immediately returning to zero after startup fails, and after waiting for 20-30 minutes, everything is normal. This usually refers not to pre tightening or contamination, but to geometric or feedback differences in the hot state. The X-500 data sheet provides the requirements for a temperature gradient of 2 ° C/h and 8 ° C/day, with an absolute mode preheating time of 2 hours, indicating that thermal stability is a prerequisite for being officially included in the indicators; The data tables for 300 and 500 do not list the same gradient and preheating values, but the comparison measurement relies on the relative relationship of “the same temperature, the same item”, and the thermal state will also change the reading. When this type of time correlation occurs, the first action is to record it, and the second action is to verify the preheating and environment.

The second point is whether the frequency of faults is related to the production pace. There are two types of problems: running continuously for half a day once and running every item at once. The former refers to pollution or cumulative heat effects, while the latter refers to geometry and assembly. Article 3: Does the fault only occur in a certain segment of the program. If a program repeatedly fails and changes to normal, it often indicates that the problem is related to a specific motion path or posture. The direction of investigation is whether the posture passed by the path causes a certain strut to switch the direction of force.

3. Disposal layer: action sequences and safety prompts for different scenarios

3.1 Pre tightening and Backlash: Where is the boundary from judgment to adjustment

The pre tightening adjustment parameters of the Equator drive unit have not been officially disclosed, including the pre tightening force value, adjustment point position, and fastener torque value. There is no official basis for any tutorial on how many cows and meters to hit, and following it carries the risk of damaging the mating surface. This section of the action is divided into two stages: judgment stage (can be completed on site) and adjustment stage (requires conditions and executed by professionals).

Step 5 of judgment: Fixed working conditions, record environmental temperature, temperature gradient, and preheating time (data across temperature bands cannot be compared); Perform tactile screening according to section 2.1; Measure the bidirectional positioning difference at three positions according to 2.2, 10 times in each direction; Approaching the same direction continuously for 10 times and taking the range; Arrange the three results side by side with the historical baseline of the machine, and determine according to Table 1 whether pre tightening or transmission clearance is the main factor, or ball joint is the main factor.

The three prerequisites for adjusting the section are indispensable: having a complete baseline and disassembly record of the machine (otherwise, it is unknown whether it will improve or deteriorate after adjustment); There are controllable measurement conditions (temperature, probe status, clamping); There is a clear verification process after reinstallation (Section 5). Missing any item, the correct solution is to continue collecting data rather than manually adjusting it.

3.2 Grating Reading Head: Practical Sequence for Cleaning and Inspection

Power off and wait: Follow the power off process in the official manual and do not touch the reading head and cable with electricity.
External visual inspection: Observe the area between the reading head and the ruler surface, and record the type and distribution of pollution. Location information is more valuable than pollution itself – pollution concentrated in a certain section of the journey often points to sealing or shielding issues in that section.
Dry cleaning: Only use the official cleaning kit A-5504-9055, do not use cleaning agents. Cleaning is carried out unidirectionally along the direction of the ruler, without back and forth sawing or applying lateral pressure.
Cable inspection: Check the bending radius, fixing points, and joint locks of the cable at both ends of the travel. The cable issue and grating contamination are very similar (both occasional), but their disposal is completely different.
Retest after Cleaning: Cleaning is an action that changes the state, and it is necessary to redo the bidirectional positioning difference and zero return test of 2.2, and record the difference before and after cleaning. If there is no change in the deviation, it indicates that pollution is not the main cause, and we will return to the hierarchical investigation of 2.5.

Safety reminder: If any liquid is found to have entered the interior of the drive housing during cleaning, immediately stop and turn off the power. Do not turn on the power again. The official disposal method for liquid inlet requires power off, cannot be re powered on, returned to the supplier for replacement, and is not within the warranty scope. This is not conservative: when the internal circuit is electrified and in contact with liquid, the damage range will be expanded.

3.3 Zero Return Failure: Handle in Four Levels

The first layer: limit and reference point signals.Manually travel at low speed and record whether the error location is fixed; Check for pressure damage, detachment, and loose connectors on the limit related cables; Check for foreign objects or contamination near the limit trigger point. If the error location is fixed and strongly bound to a certain section of the itinerary, this layer is a suspicious point. First restore the cable and trigger area before moving down; The error location is random, and the recorded phenomenon is transferred to the second layer.

Second layer: Drive the main body.Turn off the power and manually push the direction of the strut to feel whether the resistance is uniform throughout the entire process; Turn on the power and jog at low speed, listen for any abnormal noise, check if the speed is smooth, and check if overcurrent is reported. The sudden increase in resistance during a certain period, or significant jerks in jogging speed, all point towards the power or guidance section. Stop zeroing attempt at this point – when zeroing failure is accompanied by abnormal mechanical resistance, repeating zeroing will only continue to load and expand damage without solving the problem.

Third layer: grating signal.Perform small-scale reciprocating motion near the error location and observe if the readings are continuous; Perform external cleaning and cable inspection according to section 3.2; Record the type of error in the original text. The characteristics of this layer are ‘the machine can move, but the reported position does not match the expected’ or ‘reading jumps’.

Fourth layer: Controller configuration and software.Check the software version and license status, and verify whether the configuration items related to zeroing are consistent with the records from the previous normal operation; Restart according to the official process (the Equator Manager application environment will be restored to the factory configuration state and user data will be retained, which is an established behavior of the dual environment architecture and not a fault); Check for any incomplete upgrade packages or version mismatches. The typical feature is that it will appear after changing versions or configurations, and both the mechanical and feedback sides are normal.

The general principle of four level disposal: Only change one variable at a time, and retest immediately after the change is completed. At the same time, changing the cable, cleaning the grating, and restarting the controller were successful, but it is unknown which one worked.

3.4 Geometric confirmation sequence after reinstallation

To move the drive strut, strut assembly, or any fasteners that affect geometry, the following six steps must be completed.

Step 1: Mechanical reset.Confirm that the platform can move freely in all three directions without interference or abnormal resistance; The removed fasteners should be reset according to the specifications; Complete the disassembly and assembly record form. Acceptance: The manual process is reproducible with no abnormal noise, no jamming points, and no slack.

Step 2: Leveling.Level the body according to installation requirements. Acceptance: Consistent with the horizontal state specified in the installation documents (specific tolerances are subject to the official installation manual).

Step 3: Position the six position needle changing rack.Execute the official process of locating Part 1 and Part 2 of the EQR-6 rack. Acceptance: Each workstation can be automatically identified and the needle changing coordinates are correct.

Step 4: Calibration.Complete the selected comparison process (the official MODUS programming guide provides four processes: no calibration, CMM calibration, calibration, and tolerance calibration), and record the nominal value and CMM measured deviation array in the .CAL file. Acceptance: There are no errors in the process, and the .CAL file is generated normally and can be read by the software.

Step 5: Mastering.Establish the relationship between standard parts and machine coordinate system using certified standard parts. Note that this is re mastering, not reprogramming. Acceptance: Completed without any alarms.

Step 6: Retest.Fill in the numbers item by item according to the retest record table in 5.2. Acceptance: All items are within the passing conditions and have converged in the same direction compared to before repair.

The order cannot be reversed: leveling changes the geometric reference, needle changing frame positioning changes the needle changing coordinates, calibration establishes the correspondence between nominal values and actual measurements, mastering establishes the relationship between standard parts and coordinate systems, and the input of the next step is the output of the previous step.

3.5 Disassembly and Assembly Record Form

The disassembly and assembly of the drive unit must leave marks. Table 3 can be directly copied, with few fields, but each item is useful for post reading.

Stage	Record Item	Why is it necessary to record
Pre dismantling status	Zero return result, bidirectional positioning difference, unidirectional repeatability, abnormal noise description, error message	Original text
Pre disassembly status	Environmental temperature, humidity, temperature gradient, last calibration and mastering time	When there are abnormal data in the later stage, exclude environmental and time factors first
Pre disassembly status	Removed part number (drive strut/drive housing/support strut) and position	Three struts cannot be mixed together, recorded incorrectly, subsequent interpretation is completely incorrect
Fasteners	The position of each fastening point, the number of removed parts, the number of reinstalled parts, and whether they have been reset according to specifications	Installing one less piece often appears as sporadic and irregular, making it the most difficult to investigate
Fasteners	If the torque value comes from the official manual, record it; otherwise, write ‘official manual shall prevail’	The torque value without recording the source cannot be traced in the future
Cleaning	Cleaning parts, consumables (A-5504-9055), types and distribution of contamination, whether liquid has been found	The location of contamination is a clue to sealing issues; Whether the liquid can be seen determines whether it can continue to be used
Cleaning	Changes in bidirectional positioning difference before and after cleaning	Used to determine whether pollution is the main cause of deviation
Reinstall	Reinstall sequence, geometric confirmation, and completion time and results for each of the six steps	Accurately know which step to stop at after interrupting midway
Reinstall	Calibration Process Type, `.CAL` File Identification, Mastering Standard Part Certificate Number	Evidence of Traceability of Subsequent Data
Retest	Retest all item data, probe deflection value, standard part deviation	Direct evidence of delivery acceptance
Retesting	Re examination results in the first week and month after retesting	Single compliance cannot prove the effectiveness of the repair

Suggested fixed filling method: The order of the same column on the same machine should not change with people, so that records filled in by different people can be compared horizontally. The part number column should not be simplified as “the one on the left” – once the platform posture changes, the left and right sides have no meaning.

4. Boundary layer: When must we stop

4.1 Abnormal noise accompanied by temperature rise

The abnormal noise itself does not mean that we must stop, but the combination of abnormal noise and temperature rise is. Discriminant action: jog the axis for a small section, measure the outer surface temperature of the connection area between the drive housing and the strut in a non-contact manner, and measure again every few minutes to see if it continues to rise. This is not testing the specifications – the official upper limit of the normal operating temperature of the drive unit has not been disclosed. What is being done on site is trend comparison: comparing with historical records under the same operating conditions, or comparing with two other struts. Three temperatures close to normal; If a certain one is significantly higher and continues to rise, it indicates that there is continuous energy loss along this path, which may be caused by harmful friction, guiding force, or overcurrent. Continuing to power on and jog at this time will only cause heat accumulation. The correct action is to turn off the power, stop attempting to return to zero, record the phenomenon, and submit it to a professional for evaluation.

The form of abnormal noise should also be noted: the short and rapid sound at the moment of reversing is mostly related to the air travel, the continuous sound in the constant speed section is mostly related to friction deterioration, and the priority suspicion of abnormal force or overcurrent accompanied by temperature rise.

4.2 Single axis continuous overcurrent

A single overcurrent may be due to operating conditions such as excessive load, rapid acceleration, or instantaneous jamming; Continuous overcurrent or repeated overcurrent without significant load changes indicates that there is systematic resistance in this path and it cannot be bypassed by slowing down. If overcurrent occurs and still recurs after resetting, do not continuously reset and retry – repeated resetting causes the drive section to repeatedly withstand surge currents, expanding the originally repairable component level fault into component level damage. The correct action is to cut off the power, record the original text and location of the alarm, check for visible mechanical obstacles (foreign objects, cable clamping, shield interference) on the axis, and then submit the results to a professional party who can make component level judgments.

The maintenance capability needs to be layered: the official statement “There are no user service-oriented parts inside the controller.” This sentence restricts users from repairing on their own, and the official treats internal components as complete replacement parts. The motors, drive boards, interface boards, connectors, fans, and cables related to the drive are routine objects of component level maintenance. Professional maintenance personnel can perform board level and component level repairs – but disassembly and adjustment still have the ability boundary: the transmission and guidance structures inside the drive strut, linear encoder scale body, and drive housing are not officially disclosed in terms of their structure and calibration data. In case of suspected faults, they should be stopped according to the conditions in the first half of this section. Three boundaries are simultaneously established – non original repair will render the original warranty of the component invalid, which needs to be explained in advance; After repair, the accuracy and safety must be rechecked; In case of structural deformation, scratches on the linear encoder scale body, or the need for original factory calibration or encryption upgrade package and license migration, it is still recommended to return to the original factory or business representative channel.

4.3 Damage to grating body

The contamination of the reading head and poor cable contact belong to the category of cleanable and resettable; **Scratches, delamination, fracture, and deformation on the surface of the ruler are considered as damage to the body and are not within the scope of on-site treatment. Discrimination: If there is still a strong deviation from the position after cleaning, or if there are continuous scratches, abnormal color areas, and edge warping visible on the ruler surface, it will be treated as damage to the body. At this point, stop measuring, seal the site (no longer clean, no local polishing), and record the location and length of the damage. The ruler is the feedback benchmark, and any local intervention will change its division characteristics in this section, which is precisely the reference for subsequent measurements.

This is also the specific point where ‘structural components and optical components are not within the scope of third-party capabilities’. The replacement of the main body involves geometry and calibration, and needs to be handled according to official procedures – the replacement is a part, not the entire machine.

4.4 Deformation of structural components

Structural components refer to base castings, top cover castings, support arms, parallel constraint mechanisms, and drive strut bodies. The criterion is: there is a history of impact, falling, overloading, clamping, and handling that is not fixed according to specifications, and there are deviations in the data that cannot be explained by pre tightening, ball joints, and gratings. The characteristic of deformation problems is that the data form is contradictory: the hand feel is normal, the grating reading is smooth, and the return to zero is also normal, but the standard part retest is biased in all directions, and the deviation gradually changes with position. At this point, adjusting the preload or redoing the calibration will not have an effect, as the deformation changes the geometric relationship itself.

Handling method: Stop production, record, and submit to a professional party for confirmation through specialized means. Do not repeatedly calibrate on deformed structures – calibration can absorb some system deviations, and those that cannot be absorbed will be compressed into the measurement dispersion, appearing to “pass calibration”, but the data is actually unusable.

4.5 There is another type of ‘must stop’: when it is necessary to determine the qualified range

Some issues are not about whether they can be fixed, but rather about the unclear source of the judgment criteria. The pre tightening force, reading head clearance, and guide surface wear tolerance of the driving unit have not been officially disclosed; The rumors circulating on site about ‘how many micrometers should be’ and ‘how many Newton meters should be’ cannot be trusted without a source. Whenever it is necessary to determine whether the pre tightening is still within the qualified range, the random document should be used as the standard; When not specified in the manual, it can only be compared with the local historical baseline, expressed as’ consistent with baseline ‘or’ deviating from baseline ‘.

5. Verification layer: How to prove that it has been fixed after repair

5.1 Three layer structure for verification

The successful zeroing only indicates that the reference point can be found, and does not indicate that the geometry and accuracy are normal. Verification is divided into three layers:

–Functional layer: Can the process be completed normally. Return to zero successfully, needle replacement is normal, calibration is error free, mastering is completed, and the program can run completely.
–Data layer: Whether the data is within the expected range. Bidirectional positioning difference, one-way repeatability, standard component retest deviation, probe deflection value, compared with the baseline before disassembly and the historical baseline of the machine.
– Stability layer: Can the state be maintained. Whether the re inspection results of the first week, first month, and first quarter converge in the same direction.

Only when all three floors are passed can it be called repaired. Only passing through the functional layer is the most common ‘fake fix’ – the machine can run, the data is biased, and by the time it is discovered, the parts have already been batched.

5.2 Retesting Record Form

Table 4 shows the retest items and passing conditions after maintenance. All specific numerical values are labeled with their sources; Officially undisclosed, written as a comparison with the baseline of this device.

Serial number	Project	Record content	Passing conditions	Numerical source
1	Environment	Temperature, humidity, temperature gradient, measurement time	Temperature within the selected aperture band (+5~+50 ° C or+10~+40 ° C, whichever is higher); Humidity ≤ 80% RH at 40 ° C Non condensing	Official Data Sheet
2	Return to zero	Whether it was successful in one attempt and whether there were any errors	Once successful and without errors	Functional criteria
3	Probe deflection	Deflection value	≤ 4 μ m	Official usage guide common error table
4	Texture tolerance	Three way push-pull results	No starting empty distance, or no reproduction after four attempts	On site criteria
5	Bi directional positioning difference	Mean difference between forward and reverse directions of three positions	Returned to the baseline range of the machine and significantly reduced compared to before the repair	Historical baseline of the machine
6	Unidirectional repeatability	Unidirectional 10 time range	Range returns to local baseline range	Local historical baseline
7	Retesting of standard parts	Deviation and 10 times range	Deviation within acceptable range (the range is subject to the standard part certificate and internal specifications, and the specific values are subject to the official data sheet/manual); Controllable Range	Standard Component Certificates and Internal Specifications
8	Needle changing rack	Identification and needle changing coordinates of each workstation	All workstations are normal	Official process
9	Abnormal noise and temperature rise	Description of sound on each axis, temperature trend on the surface of the shell	No abnormal noise; Three axis temperature is close and does not increase with time	On site criterion
10	Stability	First week, first month, and first quarter re inspection records	Three results converged in the same direction, all fluctuating around the baseline	Ledger

5.3 Three principles for acceptance judgment

Compared to baseline, not compared to common numbers.The repaired data should be compared with the machine’s own historical baseline, which is taken from the status of new machine acceptance, environmental compliance, and qualified probe deflection. The qualified value of other machines is meaningless for this one because the assembly status of the struts, the history of fasteners, and the strength of use are all different.

Look at trends, not individual points.Retesting once to meet the standard only indicates that it is possible at this moment, but it does not indicate stability. Three times in the first week, once in the first month, and once in the first quarter, with consistent direction (fluctuating near the baseline without monotonic drift), are considered fixed.

Multiple indicators converge simultaneously.If only one of the three items, namely bidirectional positioning difference, unidirectional repeatability, and standard part deviation, improves while the other two remain unchanged, it indicates incomplete handling or other factors. The convergence of the three terms in the same direction is the strongest evidence.

5.4 One desensitization case: successful zeroing but incorrect data

An Equator 500 from a certain 3C precision structural component factory (anonymous due to customer confidentiality requirements) reported zero timeout. Follow the layering sequence: The first layer is manually driven at low speed to complete the stroke, and the error location is fixed at one end of the stroke, which happens to be the minimum bending radius of a certain strut cable. The cable is compressed by the edge of the protective cover for a long time, resulting in indentation. After cable processing and routing, return to zero and restore.

But during the retest, the needle replacement was normal and there were no errors in the calibration, but the standard parts were systematically biased during a certain stroke. Perform bidirectional positioning difference according to 2.2, and the difference between the three positions will increase in sequence, strongly binding to the position (in the form of “gap deviation or scale surface problem” in 2.4, rather than random jumping due to pollution). Cleaning is ineffective, and the feedback chain will be evaluated by a professional party. The conclusion is consistent with the local damage on the measuring surface.

Two points worth noting: zero recovery does not mean the problem is over, and after passing the functional layer, it must go to the data layer; The first layer is to eliminate the possibility of saving a lot of time – if the grating is cleaned from the beginning and all the cleaning is completed, it still cannot solve the problem of returning to zero timeout. (The case data has been desensitized and the operating conditions have been reconstructed based on real scenarios.)

Frequently Asked Questions (FAQ)

Q1: Zero reset failed, why can’t we just clean the grating reading head?

Because there are four sources of zero return failure, and grating is just one of them. The order of signal links is: limit and reference point signals, drive body, grating signals, controller configuration and software. When there is a problem with the limit, it is manifested as a “must report when walking to a fixed position”, which is not related to the grating; When the driving resistance is abnormal, it manifests as abnormal noise and uneven speed, and cleaning is also ineffective. The cost of direct cleaning is not high, but the price is to cover up the real first layer problem. The correct approach is to manually travel the entire journey at low speed, check if the error position is fixed, and first exclude the first layer.

Q2: If the platform pushes a little bit, does it mean that the preload is loose?

Not necessarily, but it should be checked first according to the pre tightening direction. There are two points to consider when judging the clearance: first, whether the direction is along the axial direction of a certain strut – the one-way clearance along the strut axis is more like the pre tensioning or transmission clearance of that strut; The second question is whether all four push and pull attempts are reproduced – the non reproduction is mostly related to the method or posture of force application. The true discrimination relies on data: if the single axis bidirectional positioning difference varies monotonically along the stroke of the strut, there is a high suspicion of pre tightening; If the difference changes irregularly with spatial position, turn to the ball joint for recheck. Additionally, it is necessary to confirm that the platform is in a free state during the push-pull process.

Q3: How to distinguish whether it is a pre tightening problem or a ball joint problem?

Take a look at the four criteria together. In terms of hand feel, the preload problem occurs along the axial direction of the strut, while the ball joint problem is that the platform as a whole can be slightly pushed and the direction changes with the point of force application; In terms of bidirectional positioning difference, the pre tensioning problem varies monotonically along the stroke of the strut, while the ball joint problem has no monotonic relationship with the stroke of the strut; In terms of one-way repeatability, the pre tightening problem is mainly manifested as mean shift, while the ball joint problem is characterized by range expansion while the mean remains basically unchanged; In terms of posture dependence, the pre tensioning problem is insensitive to platform posture, while the ball joint problem is sensitive to posture. Three out of four points point to the same side, which can be basically qualitative.

Q4: The grating reading head is dirty. Can you wipe it with alcohol?

No. The official only allows the use of cleaning kit A-5504-9055 for cleaning the relevant areas, and explicitly prohibits the use of cleaning agents. Alcohol, degreasers, and solvents can all carry away the protective layer on the optical surface, leaving residues, and may also infiltrate areas that require power-off disposal. What cannot be done is to wipe the surface of the ruler horizontally with a cloth or cotton swab – once scratches occur, the indexing characteristics of the ruler body are changed, which belongs to the category of damage to the ruler body. The nominal gap value of the reading head has not been officially disclosed, so do not try by adjusting the installation position.

Q5: After restarting the controller, the settings disappeared. Is it a fault?

It’s not a malfunction, it’s a design behavior. The controller is a dual environment architecture, with application software in a locked down state, hardware level read-only, registry read-only, no auto run, and only the Equator Home Directory in the writable area; Restart to restore to factory state but retain user data. If the parameters related to returning to zero are not user data, it is normal for them to return to their default values after restarting. What really needs to be paid attention to is version and license: upgrade packages are encrypted with version verification, and version mismatches can cause startup failures.

Q6: The abnormal noise does not affect the measurement, can we ignore it for now?

We need to check whether the abnormal noise is accompanied by temperature rise and data changes. Just the brief sound of switching direction and the data within the baseline can be recorded and observed; Continuous sound or accompanied by an increase in shell temperature over time, even if the measurement results are not temporarily out of tolerance, should be stopped – temperature rise means continuous energy loss, and continuing to operate will cause the original wear or friction to expand. The discrimination action is to jog for a short period of time and then measure the outer surface temperature, and then measure again every few minutes to compare the trend with the history and the other two struts. The official temperature limit has not been disclosed, only comparing trends rather than numbers.

Q7: The official said that there are no user repairable components inside the host, so if there is a problem with the drive unit, can it only be returned to the factory as a whole?

This sentence restricts the user to repair it themselves, which does not mean returning the entire machine to the factory. Professional maintenance providers can perform component level and board level repairs, covering driver boards, interface boards, power modules, connectors, fans, and cables. But it is necessary to confirm three boundaries at the same time: non original repair will invalidate the original warranty of the component, which needs to be explained in advance; After repair, the accuracy and safety must be rechecked; In cases of structural deformation, scratches on the linear encoder scale body, or the need for original factory calibration or permission for relocation, it is still recommended to go through the original factory or business representative channels.

Q8: After reassembly, can we start measuring the parts by simply resetting to zero and activating them?

No. Geometric confirmation must complete six steps in sequence: mechanical reset, leveling, six position needle changing frame positioning, calibration mastering, Retest. The order cannot be reversed: leveling changes the geometric reference, needle changing frame positioning changes the needle changing coordinates, calibration establishes the correspondence between nominal values and actual measurements, mastering establishes the relationship between standard parts and coordinate systems, and each step is an input for the next step. Skipping any step, the subsequent data cannot be compared with history, nor can it be used as a basis for delivery. After retesting, stability retests will be conducted for the first week, first month, and first quarter.

Data source explanation

This article is based on official Renishaw documents: Equator 300 Data Sheet H-5504-8251-06-A (2026-02), Equator 300 Specification Manual H-5504-8252-04-A, Equator 500 Data Sheet H-6078-8310-01, Equator-X 500 Data Sheet H-6620-8560-01-A (2025-06), Equator Comparison Instrument User Guide H-5504-8500 (2025), Equator Controller Technical Instructions H-5504-4000-01-A, Equator Installation and Controller Guide ID 132816/107657, Software Suite Guide ID 134769.

The part numbers of the drive strut and drive housing, the parallel structure of three linear drive struts and the grating on the rod, the lack of lead screw and belt drive, the cleaning kit A-5504-9055 (cleaning agent prohibited), the controller fan filter A-5696-0120, the controller dual environment architecture and read-only constraint, the measurement head deflection limit ≤ 4 μ m, the comparison uncertainty ± 0.002 mm, and their preconditions are all referenced from the above documents. The two official calibers of working temperature are listed in this article, and the following single version shall prevail.

The pre tightening force, fastener torque, nominal reading head clearance, guide surface wear tolerance, and upper limit of normal operating temperature of the driving unit have not been officially disclosed, and this article does not reference any undisclosed values; The four-way push-pull method, two-way positioning difference three-point measurement method, four layer investigation sequence, and three principles of acceptance and inspection cycle are common practices in the industry and are not official specifications. The case data has been desensitized.

Need a specific repair plan?

Every Equator fault eventually comes down to a specific machine type, duty cycle and batch. The criteria and procedures in this article can be used as a shop-floor checklist; when something does not add up, talk to us directly:

Item	Detail
Company	NINGBO JCE INDUSTRIAL TECHNOLOGY CO., LTD. (JCETech)
Address	Room 12B17, Building 2, Zone A, Ningbo R&D Park, Juxian Subdistrict, Hi-Tech Zone, Ningbo, Zhejiang 315048, P.R. China
Contact	Mr. Li / Mr. Zhang
Phone	+86 157-5780-7400 (Mr. Li), +86 132-2194-1413 (Mr. Zhang)
Online booking	jcetech.cn/contact

Repair intake and on-site service are handled at the same address. Please call before shipping a unit so transport and scheduling do not have to be repeated.