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
    3
    0
    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.
    [​IMG]

    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
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