Using soft limits and physical reference points to home robot arm?

Do you have a manual? There must be some process if it ever worked when new.

There is some documentation, but it does not cover homing nor provide much detail on the resolvers. Do you remember the one you worked on at the London hackspace with Dean? Its the same STMBL control box but another RX60. We were never able to find a huge amount of documentation and after a point staubli were not very forthcoming.

As far as I know it was homed manually even with the original staubli control unit, which is now dead.

Ross

And there are no specific joint encoders or limit switches, just the servo resolvers?

Its a strange one. There are cables named LS1 and LS2 which according to the schematics are limit switches. I believe they serve the first three joints and are all on a common circuit and Normally closed.

That's where it gets odd. There is continuity between the two lines, 6 ohms resistance. However when you place one of the joints into its limit, there is no change in the continuity or resistance. Its basically a short and having a joint at its limit does not appear to do anything.

Out of curiosity I also set the meter to test for diode and capacitance, but no change is observed when, under power, moving the joint to its limit. Each time the STMBL's will cut out due to amplifier fault (linuxcnc error), which I am guessing equates to a saturation error in the STMBLs.

The arm does have index marks, but unlike a KUKAs vernier lines, the ones on the staubli are just indentations or scribe lines you match up. There may have been a tool used to do it, though I find it hard to believe that was needed every time the bot was run. Apparently a manual home was needed with the original controller, but that could have been because it was on the fritz.

Wireline wrote: Its a strange one. There are cables named LS1 and LS2 which according to the schematics are limit switches. I believe they serve the first three joints and are all on a common circuit and Normally closed.

Are they microswitches or something else? Have you ever seen one?

I've had a rummage around inside the housing to see if I can spot them but no luck. The exploded diagrams dont seem to show the physical bodies either.

They are present on the drawings, and originally went to the safety board of the CS7M controller, sitting in a big series line with lots of other Estop kit.

Putting an ear to the unit, there is a faint click when it reaches its stop, but I am grasping t straws really. One option might be to fit some switches myself.