PCMCIA Card Destroys PLC Power Supply

This happened yesterday. I plugged into an AB PanelView 600 using DH-485 cable through a PCMCIA card in order to back up the HMI file. I could not get connected and gave up. HOWEVER....I noticed that the HMI could not find the PLC any longer. When I opened the control cabinet, the SLC500 (5/03) PLC was dead. The power supply had gone out. I thought coincidence; it has nothing to do with me connecting to the HMI. However after replacing the PLC power supply, I tried again to connect to the HMI. Another PLC power supply got destroyed. Is there an issue I am not aware of???

I connected to a DL06 via RS232 one time and burned up the PLC port as well as burned out my RS232 port and burned a hole in the bottom of my laptop. Come to find out, the electrician did not ground the PLC and so It used my laptop as a ground (It was a Dell laptop back when they had a metal base). If the PLC, HMI, and your PC are not properly grounded, then it would not surprise me that you are burning up power supplies by connecting.

What were the part numbers on the parts you were using and of the HMI

The PLC (5/03) has 24VDC on the DH485 port so if something got crossed there is a good chance that it would burn something up

What does not make a lot of sense is that plugging straight into the HMI would burn the PLC power supply, did you unplug the PLC to connect to the HMI?

I doubt the power supplies are destroyed. They were probably in overcurrent shutdown. Power cycle for 30 seconds or so to recover.

Check 24VDC to ground voltage.
Check 0VDC to panel ground voltage.

Check 0VDC to 120V laptop outlet ground voltage.
Check panel ground to 120V laptop outlet ground voltage.