scarince
Lifetime Supporting Member
I feel like this should be obvious, but I'm not seeing it:
A vendor is building us a machine that has a spindle controlled with a PowerFlex525.
The spindle is enclosed by a removable guard that employs dual-channel safety switches. PLe is required for the hazard.
This would be a straightforward application for safe-torque-off *except* that we will have a jog circuit to turn the spindle at low speed when the guard is open and the operator is depressing a Schmersal enabling switch. The idea is that in jog mode with the guard open the spindle would be limited to very low speed.
I'm hung up on how to "enforce" that the drive will run at low speed. I can imagine how the jog-enable would provide the required inputs to enable the drive and the safe-torque-off, but I don't know how you insure the drive can only run at X% speed.
They are currently not using the ethernet interface at all...all hard wiring to the I/O board and analog input for speed control.
Of course any robot can do this, but that velocity-limiting seems to be "built in", and I've never given any thought to how that is controlled.
Has anyone seen this / done this before? Is this even possible to do?
Thanks!
A vendor is building us a machine that has a spindle controlled with a PowerFlex525.
The spindle is enclosed by a removable guard that employs dual-channel safety switches. PLe is required for the hazard.
This would be a straightforward application for safe-torque-off *except* that we will have a jog circuit to turn the spindle at low speed when the guard is open and the operator is depressing a Schmersal enabling switch. The idea is that in jog mode with the guard open the spindle would be limited to very low speed.
I'm hung up on how to "enforce" that the drive will run at low speed. I can imagine how the jog-enable would provide the required inputs to enable the drive and the safe-torque-off, but I don't know how you insure the drive can only run at X% speed.
They are currently not using the ethernet interface at all...all hard wiring to the I/O board and analog input for speed control.
Of course any robot can do this, but that velocity-limiting seems to be "built in", and I've never given any thought to how that is controlled.
Has anyone seen this / done this before? Is this even possible to do?
Thanks!