plm plugged into 4 port router

[carranoelectric]

My plm will not communicate with the modules and I have the plm plugged into my 4 port router, when I plug the isy26 into the router the red pilot light lights up for the port being used but when I plug the plm into the router no pilot light lights up. could this be the reason for the communication problem. I'm using a standard 3 ft cat 5 cord to connect the plm to the router.

[Sub-Routine]

The PLM should be plugged into the wall and the UD serial cable should connect it to the ISY. Only the ISY should be connected to the router.

 

Rand

[jbev]

Yes, plugging the PLM into the router directly is not how how its suposed to be done. I doubt any damage was done (I haven't tried that experiment for myself) but I would definately disconnect it and put the PLM into Port A on the ISY using the supplied cable. Then run your ethernet cable from the ISY to the router and see if anything changes or improves.

[Brian H]

The RJ45 connector on the PLM is not a network type connection. It has both Serial and +12 Volts power on it. You may or may not have done harm to the PLM or router. It may have blown the protective +12 volt fuse in the PLM; but if the interface connected to it nromally does not use power from it . It may not matter.

The RS232 Interface Chip could also be bad, though they are usually quite harty.

[Michel Kohanim]

Brian H,

 

Thanks so very much for your input. I confirm that the RS232 Level Shifter chips are quite sensitive and, in all likelihood, the PLM is now bad (we have reproduced this in the lab: connect your PLM to your router and the PLM shall no longer respond to any serial commands).

 

Thanks again,

With kind regards,

Michel

The RJ45 connector on the PLM is not a network type connection. It has both Serial and +12 Volts power on it. You may or may not have done harm to the PLM or router. It may have blown the protective +12 volt fuse in the PLM; but if the interface connected to it nromally does not use power from it . It may not matter.

The RS232 Interface Chip could also be bad, though they are usually quite harty.

[Brian H]

If I looked at the normal network cabling diagram correctly. Pair 3 of a network is PLM is +12 volts on one pin and RS232 Out on the other pin. Loop through a network coil and +12 is tied back to RS232 Out. Ouch!