Axis Selector and Safety

Robot Controller
1

Has anybody used an axis selector with multiple safety zone systems?

Very little documentation is available for it, and details seem scarce when asking questions.
I get the impression that it is the old-school approach used before software safety systems.

My understanding
“One to Many” Multiplex control box that connects a positioner (any or motor) to a controller drive

Provides:

  1. Sole drive to one positioner at a time from a selection of 2 -3 Positioners (say L type)
  2. Acts as a Safety Isolator for an operator to unload the non-selected positioners

Questions:

  • Is it safety rated, i.e. Pld/Cat3 for the positioner?
  • How does/did it limit robot motion to protect the operator from the robot?
  • Seems you still need SafeMove, but dual positioners seem to pre-date safemove?
  • All I can think of is some old-school arrangement with electronic limit switches and multiplexing axis 1

If that is all correct,
I’m assuming the motors and gear ratio need to be matched?
i.e Example on K or R type Postioner

  1. Side 1 & 2 run off the same driver, and therefore, the same external axis index for the common part program between sides
  2. Must the station index actuation be a separate drive?
2
  • There is one drive for the interchange and depending on the option taken one drive for the positioners, or a drive for each positioner. With L positioners the limitation is the number of contactors that can be fitted on the axis selector swing arm. The gear ration, motor size, etc configuration is done in the motion configuration file so when you activate a given positioner the correct parameters are used.
    -You can purchase the system with a safety controller for the positioners or without, for the second option you would have to make the system CAT3 compliant.
    -Robot motion only needs to be limited for none interchange positioners, and these days SafeMove would be used for this (used to be safety rated limit switches on axis 1).
3

Awesome, thanks very much Graeme