1. CMOS latchup from ESD event (a.k.a. EOS event)
2. NOP loop waiting for IRQ
3. No sign of life in sanity timer output ( bad design)
4. no self monitor for reliability of PLC . auto self-test... auto check feedback loop
5. fried PLC from back EMF and lack of protection
6. least likely defective part ( unless blown from failure to recognize risks and design protection)
7. most likely defective EMC design.
Typical debug skills doing mental transfer function on each component. Output vs input. for both current and voltage.. Also back drive outputs to see if active using 1KΩ or whatever to pull up down. It's all an application of Ohm's Law and understanding specs for system and parts.
If the Run command indication on the drive is lit continuously and the stop command indication on the drive blinks at the same time , then what could be the cause of the problem ?
i measure the DC volts when it was running perfectly before the problem occurs , the DC volts keep on increasing from 0.35 Vdc to about 3.65 Vdc .......... from the slowest to the fastest speed of the machine
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i measure the DC volts when it was running perfectly before the problem occurs , the DC volts keep on increasing from 0.35 Vdc to about 3.65 Vdc .......... from the slowest to the fastest speed of the machine
If the Run command indication on the drive is lit continuously and the stop command indication on the drive blinks at the same time , then what could be the cause of the problem ?