PLC S7-1200 PTO square pulse distortion

Discussion in 'General Electronics Chat' started by tn88test, May 8, 2013.

  1. tn88test

    Thread Starter New Member

    Mar 14, 2013
    I'm using Siemens CPU 1214C, DC/DC/DC. So far I only connected the CPU to power supply.
    I had been able to create PTO. When I check the output signal with my oscilloscope at 50Hz, the square pulse is distorted.

    But if I put a resistor in between output and ground and I measure it. It give me perfect square wave pulse.

    Maybe the CPU is damaged. There had been 4,5 fuse break current overload to the CPU. I had checked input and output, the CPU seems likely works fine.

    Can anyone explain me this? Thank you!
    Last edited: May 8, 2013