I've read stories about PLM being the weakest link in the Isy system.

What's the telltale sign?

Is it a good idea to have a back-up PLM ready even before there are troubling signs?

I determined I had an issue only because my on-at-dusk lighting events stopped working, but program was still running

 

See here for more:  

 

This is a real long thread on the 2413S PLM and its failures. https://forum.universal-devices.com/topic/13866-repair-of-2413s-plm-when-the-power-supply-fails/

If you look at the label on the back. It should have a Hardware Revision number and a Date Code.  I know hardware revisions higher than 2.5 have improved capacitors and a updated serial port. With more protection on the serial signals. I suspect they should be more releasable.

1 hour ago, ISY Newbie said:

I've read stories about PLM being the weakest link in the Isy system.

What's the telltale sign?

Is it a good idea to have a back-up PLM ready even before there are troubling signs?

How old is your plm? It would help more if you would share what problems you're having vs having tunnel vision and focusing on what you think it is. 

Most issues people have isn't because of their PLM. Many times, its either noise (poor communication) or poor installation (including programming and/or setup)

22 minutes ago, lilyoyo1 said:

How old is your plm? It would help more if you would share what problems you're having vs having tunnel vision and focusing on what you think it is. 

Most issues people have isn't because of their PLM. Many times, its either noise (poor communication) or poor installation (including programming and/or setup)

I don't have any issue yet. I'm trying to prevent a situation where my PLM dies and I need to wait a few days before its replacement arrives.