u/roxelamstart

First of all, I am an absolute beginner with industrial robots. This is my first robot and purely a hobby project, so please excuse any incorrect terminology.

Thanks again for all the help on my previous posts.
The main problem is now very reproducible: Before running CALIBRATE, the robot can be jogged, but I get a Disturbance Excess warning. After CALIBRATE, J2 repeatedly trips SRVO-050 Collision Detect.

The fault is strongly load-dependent. J2 can move at around 15–20% jog speed in the rear part of its range, where less lifting torque is required. As soon as the arm moves forward past the tipping point and J2 has to work harder against gravity, SRVO-050 occurs almost immediately. J3 can now also produce the same alarm when jogged quickly.

I replaced the clearly stiff J2 motor with an identical motor that rotates freely. This noticeably improved movement but did not solve the fault.

The J2 and J3 brakes release correctly with approximately 90 VDC. Motor phase resistances are balanced, with no continuity to ground. The three-phase input measures approximately 235 VAC between all phase pairs.
I also swapped the complete J2 and J3 amplifier channels, including JV2B/JV3B and the corresponding U/V/W outputs. The fault remained associated with J2. Both reducers have also been inspected and reassembled. No tool or payload is attached.

One J2 mechanical stopper was badly bent, so the robot has clearly suffered a serious collision in the past. However, because J3 now also faults under higher acceleration, I am wondering whether this could be a shared problem.
My current suspects are voltage dropping under load, incorrect High-Speed robot or servo parameters after reinitialization, a shared PSM/amplifier/control-board problem, or a cable fault that only appears under load.
Would you check the dynamic power supply first, or concentrate on the robot and servo parameter set?
Reference values or screenshots from an LR Mate 100i High Speed with an R-J2 Mate controller would be extremely helpful.

I posted about this issue recently, but since then I have done a lot more testing and found a much more specific and repeatable pattern. The key new finding is that J2 works normally after Zero Position Mastering and only fails immediately after CALIBRATE.

I have a used FANUC LR Mate 100i High Speed with an R-J2 Mate controller. After replacing the robot-side pulse coder batteries, I performed Zero Position Mastering using the witness marks.
The unusual behavior is fully repeatable:
Perform Zero Position Master
Do not run CALIBRATE yet
All five axes, including J2, work normally
J2 can be jogged repeatedly for an extended time, in both directions and at different positions
The J2 brake engages after the configured delay and releases normally again
Pulse feedback follows movement correctly and position error stays near zero
As soon as I run CALIBRATE, J2 stops working
The first J2 jog command at 1% immediately produces:

SRVO-050 CLALM alarm (Grp:1 Ax:2)

After CALIBRATE, the torque monitor for J2 rises sharply, but the encoder changes by only about 164 pulses before the alarm. Before CALIBRATE, J2 moved more than 1.1 million pulses normally with almost zero following error.
Already checked:
J1, J3, J4 and J5 work normally
J3 can be jogged normally
J2 brake repeatedly engages and releases correctly before CALIBRATE
All controller and robot connectors were cleaned and reseated
$SV_OFF_ALL and $SV_OFF_ENB were checked against the original configuration
Temporarily changing the J2 servo-off/brake parameters made no difference
$MASTER_COUN remains unchanged before and after CALIBRATE
$MASTER_DONE = TRUE
Single Axis Master status is 2 for all five axes
Motor IDs and servo parameter IDs are identical and plausible for all five axes
Active payload is 0 kg with no tool attached
J2 pulse feedback is stable and plausible before CALIBRATE

No unusual mechanical noise or resistance while J2 is working
This makes a permanent brake, motor, cable, gearbox or servo-amplifier fault seem unlikely, because the same hardware can run normally for as long as I want until CALIBRATE is executed.
Has anyone seen an R-J2 where CALIBRATE activates an incorrect J2 position, compensation or servo parameter state? Which R-J2 variables specifically become active during CALIBRATE and could cause J2 to produce high torque with almost no movement?

Hi everyone,

I’m not sure whether this is the right place to ask, so please excuse me if this is outside the usual scope of the subreddit.

I’m only a hobbyist, not a robotics technician. This old FANUC LR Mate 100i with an R-J2 controller more or less “followed me home” after I found it cheaply. I managed to get it running myself by fixing the safety circuit, replacing the dead Pulsecoder batteries, clearing the BZAL alarms and remastering it.

Now I have one strange problem:
Directly after Zero Position Mastering and calibration, all five axes work normally. After switching the controller off and back on, J2 sometimes becomes almost completely locked.

When jogging J2:
J2 barely moves, J3 twitches slightly
The controller shows SRVO-050 CLALM, Group 1, Axis 2

All other axes still work
J2 is far away from its mechanical limit
If I perform Zero Position Mastering again, J2 immediately works perfectly until the next power cycle.

One possibly important detail: before this started, I accidentally jogged J3 into its mechanical stop. Instead of simply stopping, the arm snapped back very quickly.

I’m currently wondering about:
-Mastering or Pulsecoder data not being retained
-J2 brake not releasing
-A connector or motor cable issue
-The J2 servo amplifier channel
-Mechanical damage from the J3 end-stop incident

What confuses me most is why remastering temporarily fixes the problem.

Any advice would be greatly appreciated. Please keep in mind that I’m learning as I go and trying to keep this old robot alive.

Thanks!