RC input used by Siemens S7 1200 PWM

Have a nice day!
The RC input has got the Siemens S7 1200 PLC PWM output sign. The parameters: Umax=5.05V; freq=5kHz. The GND has got the PWM output null.
The motor stoped beacause of invalid input.
What should I do?
Thanks in advance: S. Zalán


It sounds like you might be sending a duty-cycle based PWM signal instead of a hobby RC servo signal. A typical RC signal has a pulse width range between 1000µs and 2000µs and a period of 20ms (i.e. a frequency of 50 Hz).

Unfortunately, I am not very familiar with that PLC, so I cannot offer specific advice about how to use it. If your PLC can use the Jrk’s TTL serial or I2C interfaces, one of those might be worth considering since they offer more control than the RC interface.

By the way, I am not sure what you mean when you say “the GND has got the PWM output null” but it sounds like you might be using some kind of GPIO on your PLC as a ground connection; in general this is not good practice and some devices can have erratic behavior on the GPIO pins when booting up, which could cause problems (and potentially damage).