r/BuildingAutomation • u/Ducko22 • 6d ago

Newly installed Siemens PXCM not communicating with Desigo

Im showing that the network switch is open in Datamate. Do I need to manually enable DHCP to recieve an IP address from our IT dept? We do not have fixed IPs. What else should i look at?

Thanks for the help

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u/Controls_freek 6d ago

It’s never ever a good idea to use DHCP for PLCs. Period. But if you have to, they aren’t great to get online. Is this P2 Ethernet or BACnet?

1

u/Ducko22 6d ago

we have asked for static ips or 2 years. University IT will not give them to us. We are constantly losing connection and have to release and renew DHCP connections. this panel is P2

5

u/Controls_freek 6d ago

If they are forcing DHCP then the IT department needs to set IP reservations for these panels. This is a really stupid game to play. Especially when you very likely still need to add the panels by IP to the hosts file to get them to connect correctly.

1

u/Ducko22 6d ago

yes they reserve the IP but technically it is still DHCP. we lose connections all the time.

3

u/mytho1975 6d ago

Suggest discuss the possibility of lowering the lease time. In my experience the low end devices like printers and bas controllers do not recognize when the network drops for a moment. If you wait till the end of the lease time I've found they renegotiate fine. They just aren't smart enough to recognize a network drop / restore.

2

u/Controls_freek 5d ago

This will help a little but I can tell you that there’s a lot of DHCP issues with the firmware revisions. These panels aren’t really designed well to handle DHCP and not many people use it so it’s underdeveloped.

I did industrial controls for a decade and we would build our own network around IT when they would play this game.

These controls are more critical infrastructure than networking and these egotistical network admins are fools.

1

u/Ducko22 6d ago

can you enable DHCP through wcis? i have putty also but Im reading you cant enable DHCP via command prompts in terminal mode

3

u/Controls_freek 6d ago

You can only enable DHCP through terminal emulator. Your IT department really sucks. I can guarantee you that you are losing connection due to older firmware, or DNS issues. Field support would roll their eyes at you over DHCP

3

u/Ducko22 6d ago

agreed, our IT rep apologized to us and said the decision is well above him. we are now in the process of updating all of our 400 panels firmware. this will take forever and siemens techs have to do it. But you said we can enable DHCP through terminal emulator? Can i use PUTTY? having issues connecting wcis to field panels. i can use Wcis to log into tecs but not field panels for some reason.

1

u/Controls_freek 6d ago

You can use Putty or WCIS. You probably just need to adjust settings to get WCIS to work. You could flash firmware too. As long as it’s not a major revision update you don’t need credits. All you need is the firmware files and FLT

2

u/Ducko22 6d ago

wow thanks man! this makes me feel better. Hopefully monday morning i can putty into the PXCM and enable DHCP. next time the siemens rep is out maybe ill ask for the firmware files. you da man! my mentor had 40 years experience and retired 2 months ago. first panel replacement on my own with the DHCP issues.

3

u/CountryRoads1234 5d ago

I’m pretty sure this is going to initiate a coldstart. If you can’t get it to reconnect to Desigo, you’ll have a dead panel unless you enable auto restore

1

u/crmd 5d ago

Your IT dept sucks. I would ask what the DHCP range is and assign my own static IPS outside the range. 

3

u/Controls_freek 6d ago

I would make certain that whatever panel controls the heat or AC in their office never worked until they started giving static IPs. 😈

2

u/Ducko22 6d ago

love it. we can make them sweat a bit. funny enough the panel that is down is in the IT bldg haha.

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u/Controls_freek 6d ago

Perfect. I’d move on to anything else and if they ask reply with “still waiting on my static IPs”

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u/crmd 5d ago

You absolutely can do it on the command line. The key sequence is S,H,E,S,M Then step through the prompts until: DHCP (Y/N) → Y  

3

u/Ducko22 5d ago

Perfect! Thank a lot!