tommy23t
Member
Hi all:
I am using an A/B Micrologix 1200 to control a stepper. The system is running fine, but I need to add a "stall" detect. I am using it a little different than intended, I think. My application is to rotate a product, sense a tab, and continue to rotate to a specific position from that tab. Short version of sequence as follows:
1) turn stepper output on, PTO:0.HIP set to 30000 pulses (generate error as process did not complete if the hi preset is reached)
2) On a signal from a sensor, enable and start the count HSC:0.CE(input from encoder)
3) When count (position) setpoint is reached, set the PTO:0.CS (controlled stop) bit. Product decels, stops, and the next process begins with the product in register.
I am having trouble figuring how to detect a stall. I know I have a pulse train going out, but my count may or may not be enabled yet, as the product may not have reached the reference sensor. If I didn't get to the sensor to start the count yet, the PTO:0.TOP <= PTO:0.OPP will go true and stop the process as an error (after 30K pulses and a noticeable racket). I don't think I can monitor the encoder input until I start the registration sequence and enable the counter. I tried comparing the PTO:0.OPP (output pulses generated) with the count HSC:0.ACC, but with hit and miss results. I would appreciate any suggestions.
-tommy23t
I am using an A/B Micrologix 1200 to control a stepper. The system is running fine, but I need to add a "stall" detect. I am using it a little different than intended, I think. My application is to rotate a product, sense a tab, and continue to rotate to a specific position from that tab. Short version of sequence as follows:
1) turn stepper output on, PTO:0.HIP set to 30000 pulses (generate error as process did not complete if the hi preset is reached)
2) On a signal from a sensor, enable and start the count HSC:0.CE(input from encoder)
3) When count (position) setpoint is reached, set the PTO:0.CS (controlled stop) bit. Product decels, stops, and the next process begins with the product in register.
I am having trouble figuring how to detect a stall. I know I have a pulse train going out, but my count may or may not be enabled yet, as the product may not have reached the reference sensor. If I didn't get to the sensor to start the count yet, the PTO:0.TOP <= PTO:0.OPP will go true and stop the process as an error (after 30K pulses and a noticeable racket). I don't think I can monitor the encoder input until I start the registration sequence and enable the counter. I tried comparing the PTO:0.OPP (output pulses generated) with the count HSC:0.ACC, but with hit and miss results. I would appreciate any suggestions.
-tommy23t