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Siemens S7-1200 relay problem

Siemens S7-1200 relay problem

Siemens S7-1200 relay problem

(OP)
I have problem with hanging relays in S7-1200 main CPU unit.
After a couple of weeks on and off (30sec)with a small load my outputs starts to hang.
I have seen this on my two instalation and it looks like bad quality on the used relays in the CPU.
My load is a EXx saftey barriar 9176 fron Stahl, data sheet added to the thred.
Cant see any reason for this problem, please help?

RE: Siemens S7-1200 relay problem

S7-1200 CPU comes with transistor outputs, not relays.  What is the complete part number of your CPU?

Are you turning on/off the relays using any counters?  If so, then check if the counters are reaching their maximum values.

RE: Siemens S7-1200 relay problem

(OP)
The CPU is 1214C DC/DC/Relay.
My load is non inductive and only 60mA
On and off 30s,
starts to get problem after a couple of week usage

RE: Siemens S7-1200 relay problem

Cable length? Those rather tiny relays can't take much capacitive loading before they weld. You may need series resistors to reduce the charging current.

BTW: Is it Johan?

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: Siemens S7-1200 relay problem

(OP)
Yes its Johan
Im using a safty barrier directly connected to the PLC.
EXx ia  

RE: Siemens S7-1200 relay problem

(OP)
Siemens asked me to add diods, cant see any reason its not inductiv load....
 

RE: Siemens S7-1200 relay problem

Well, you know Siemens, Stockholm...

Where are your systems? Anywhere near me?

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: Siemens S7-1200 relay problem

(OP)
Boden and Norrköping
Do you still have skype
 

RE: Siemens S7-1200 relay problem

Yes, but I have mixed up skype names and computers. I don't know any more if it is Skogsgurra, Skogsgurra1 or Skogsgurra11. But my phone number is on our home page. So is the e-mail address.

I will visit Braviken soon. Is that where your system is? I have just bought a fast contactless current probe (5 MHz 10 mA-20 A) that may come in handy.

I can pop in and have a look when I go there. Won't cost you a dime - but you'll have to buy me lunch or dinner.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

RE: Siemens S7-1200 relay problem

(OP)
Deal
Give you a call tomorrow
/Johan

RE: Siemens S7-1200 relay problem

OK.

Gunnar Englund
www.gke.org
--------------------------------------
Half full - Half empty? I don't mind. It's what in it that counts.

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