Hello automation experts,
I'm trying to learn about servo axis control in AB ControlLogix PLCs (L33ERMS).
Attached is an example of a servo routine.
I need a help understanding this part of a program.
It seems to me that it is working in the following way:
User will enter command via HMI, this will be transferred in the UDT (User DataType) in the PLC program. ServoAxis.ActualPos is HMI variable while ServoParameter.ActualPos is actual variable for the drive control. It is initialized to zero.
Now, when boolean variable .StartServo is set to 1 (probably from HMI), there will be one shot execution that will reset the bit _Start.PC (or set it to zero), and it will also execute MAM block (but only for one cycle).
When _Start.PC is set to zero (unlatched) in network nr. 2, the variable.StartServo will NOT be unlatched, since condition is not true.
I have prior experience only with TIA portal and not with AB PLCs, but this logic is really looking strange to me.
Maybe I'm missing something here, but it looks like to me that rung 3 is not quite correct.
Any help in clarification is appreciated.
Thank you.
I'm trying to learn about servo axis control in AB ControlLogix PLCs (L33ERMS).
Attached is an example of a servo routine.
I need a help understanding this part of a program.
It seems to me that it is working in the following way:
User will enter command via HMI, this will be transferred in the UDT (User DataType) in the PLC program. ServoAxis.ActualPos is HMI variable while ServoParameter.ActualPos is actual variable for the drive control. It is initialized to zero.
Now, when boolean variable .StartServo is set to 1 (probably from HMI), there will be one shot execution that will reset the bit _Start.PC (or set it to zero), and it will also execute MAM block (but only for one cycle).
When _Start.PC is set to zero (unlatched) in network nr. 2, the variable.StartServo will NOT be unlatched, since condition is not true.
I have prior experience only with TIA portal and not with AB PLCs, but this logic is really looking strange to me.
Maybe I'm missing something here, but it looks like to me that rung 3 is not quite correct.
Any help in clarification is appreciated.
Thank you.