1/10/2020 12:21 PM | |
Joined: 9/27/2006 Last visit: 6/5/2024 Posts: 12260 Rating: (2670) |
Hello siapth_veh; Are you trying to drive a simple stepper motor with a varying analog voltage, or do you have a specialized interface that accepts analog voltage input signals to control the stepper? I ask this because the usual way of moving a stepper motor is by a microstepping program, using PWM ( or PTO) outputs. See this article for the basic theory: https://www.digikey.com/eewiki/display/Motley/How+to+Drive+a+Stepper+Motor This FAQ points to stepper motion control information with a S7-1200 CPU. Hope this helps, |
1/11/2020 10:50 PM | |
Joined: 9/27/2006 Last visit: 6/5/2024 Posts: 12260 Rating: (2670) |
Hello siath_veh; I can find no examples of PWM signal control through a potentiometer input, in Siemens Product Support or the forum. Here are some other sources of information that should be helpful: First, the following video shows the generation of a PWM signal on a S7-1200 CPU with DC outputs (os DC signal board), and the control of the duration of the pulse with analog signals (which you can control with a potentiometer in your project): https://www.youtube.com/watch?v=s8Q1yi5KB3Y Note that you will need a power module (stepper amplifier, stepper drive) to enable the stepper motor that you want to control through the PWM signal from your PLC. For basic information on the S7-1200 PWM controls, read Rinat98's post in the following thread: https://support.industry.siemens.com/tf//ww/en/posts/s7-1200-pwm-how-to-do/118343?page=0&pageSize=10 The details for the CTRL_PWM instruction shown in the screenshot below are taken from the S7-1200 Easy Book. The following FAQ will help you understand how a value coming from your potentiometer can be moved to the output value of your pulse output to change the pulse duration dynamically: In STEP 7 (TIA Portal), how do you change the pulse length for the pulse width modulation (PWM) in the user program of the S7-1200 CPU? https://support.industry.siemens.com/cs/ww/en/view/63200733 Hope this helps, Daniel Chartier |
Last edited by: dchartier at: 01/11/2020 23:14:35 |
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