Help With PWM command

[smichalo 0]

Hello I was wondering if someone can help answer a question. I have a CP1L PLC with pulse outputs. I would like to connect to an AMCI stepper motor and controller just to play around with. Before I connect I wanted to program the PLC to send the pulses to the stepper controller using the PWM (891) command and the INI (880) to stop the pulse train. I set up the 891 command like this: ( the command does have the @ in it ) Port Specifier - #0000 Frequency -#1F4 Duty Ratio -#32 I set up the 880 command like this Port Specifier - #0000 Control Data -#3 First PV word- 0 The way I understand it, for the 891, I set up pulse output 0 to run at a frequency of 500Hz with a Duty Ratio of 50% when rung 1 goes true. and 880 will stop the pulse train when rung 2 goes true. What I'm seeing is when I turn on rung 1 Output 1 starts to flash. When I turn on rung 2 nothing happens. Output 1 stays on The ony time the INI (880) works is when I set the port specifier in both commands to #1000 and it is still output 1 that comes on... I thought I had it set up to turn on output 0 and turn off output 0 Can someone help me understand this. Thanks Steve

[Sergei Troizky 26]

According to the manual, the INI instruction port specifier must be #1000 even if it is specified #0000 in the PWM. However, PWM is not intended for positioning. Use PLS2, SPED, ACC instructions. Edited 4 Feb 2012 by Sergei Troizky

[smichalo 0]

Thanks for the reply Sergei. I'm not looking to do any positioning. I just want to send the pulse train to the stepper controller and get the motor to turn. I was just using the help file that comes with CX programmer and the definitions for the PWM instruction come from there. I didn't see that the port specifier must be #1000. I will try to use the instructions you mentioned. ( I'm just experimenting and playing anyway ) Thanks Steve

[Sergei Troizky 26]

It still may require acceleration/deceleration, so the ACC is the best choice for continuous rotation.

[Jay Anthony 118]

Sergei is correct. The stepper motor will lock up unless you use some acceleration.