Created Date: November 08,2019

Created by: Cliff T.

I earlier posted about my P1K PLC not talking to the STP-DRV-4850 drive and it turned out I was using the wrong communication cable. I obtained to proper cable and now have created an "FP " move based on a one shot HMI input (start button). My expectation is that once the initial "FP " move is finished I should be able to press the "start " button again and start a new "FP " move but when I push the start button a second time nothing happens. I am not sure if this is because the "FP " is an absolute move and I am trying to move to the same place twice or if the drive still has "leftover " commands from the original "FP " move that need to be cleared out after the first move is made (note: I am trying to use a SP0 command before the FP to set initial position at 0 each time). I have attached screenshots of my logic and if necessary can post the program itself. As always, any input from this awesome community is sincerely appreciated and thank you in advance for your time.

Created Date: November 08,2019

Created by: MikeN

The "SP0 " he is sending is an ascii command, not the same as the typical SP0 in a PLC. Where a PLC that would be first scan, SP is just set position and 0 is 0 counts. It looks the same when talking about it on a web forum, but they are actually different commands and going to different areas.

Using set position 0 and then feed to position 20,000 should work, but I am wondering if there is just some interaction there that is causing issues. Like maybe you need to send the set position and execute before you send the feed to position and execute. Im not sure if that is the case or not, but Im just thinking that maybe buffering them both for execution in a single command may be causing the issue.

Either way, using feed to length is probably an easier fix and would do what you want in a single command instead of using two.

edit:

another way you could test if your SP+FP command is working or not would be to make a second button that executes a position move with an FP0. Execute the first command to move CW to 20k steps, then hit the second button and see if the stepper moves CCW backwards 20k steps. If it does, the set position is not working properly.

Created Date: November 13,2019

Created by: Todd Dice

I don't know your PLC, I see the command in your program but, if really a true sp0 command like dl6 plc then sp0 only happens on very first scan after power up or after going to run mode after program not every scan

The first scan bit in Productivity is, "First Scan Bit, " as the software is tag based and you program by tag names, not by addresses.