Originally Posted by
joeavaerage
Hi,
the way you have drawn your circuit diagram you must program the drive such the the opto-transistor is conducting IN ABSENCE of an alarm condition.
You will need to measure the voltage drop across the transistor when conducting 20mA say to determine what the VCEsat is low enough for your scheme to work.
The bigger question is why you are doing this?. Remember the ESS has a total of 51 inputs and outputs. There is no need to combine all the ALRM outputs into one circuit,
you have enough inputs to have one input per ALRM.
My new built mill has three servos, but my BoB/ESS has five servo outputs should I expand. Each of the five (potential) servos has a dedicated ALRM input to the BoB/ESS combo so that I know which
servo faulted, it shows an LED on screen. If any of the servos fault then any one or more will cause an Estop.
This means I can program each one individually to be NC or NO as best suits that particular servo. I don't have to worry about trying to wire each servo in series so the VCEsat
problem just disappears.
In the early days of Mach when everyone used a parallel port that had only five inputs you had to be creative to combine as many limits, alarms, homes etc as possible, but why do we still try to do it
now?
For instance my new mill has six limit switches (++ and a -- limit per axis), three homes switches (one per axis), and each has its own BoB/ESS input.......I mean why not I've got plenty to spare.
Craig