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[?]: Replace a 315-2PN/DP CPU
Posted: Tue Apr 02, 2013 3:36 pm
by alansal
Hi All,
In a plant i will have to switch two PLC's to try something but i don't know how.
The CPU's are identical, 6ES7-315-2EH14-0AB0 V3.1 but of course logics and configs are different.
and this is a multi project (consisting of 10+ CPU's total)
one of them is used as GW (to collect and send data via modbus), other to govern an engine.
Do i simply change the memory cards? or anything else to do in netpro as well?
Please help,
Thanks in advance.
Re: [?]: Replace a 315-2PN/DP CPU
Posted: Wed Apr 03, 2013 7:14 am
by Umencho
No, both will not work with just replacement of MMC.
Re: [?]: Replace a 315-2PN/DP CPU
Posted: Wed Apr 03, 2013 8:46 am
by sanruku
alansal wrote:
In a plant i will have to switch two PLC's to try something but i don't know how.
You DO understand that this is a BIG NO-NO, huh?
In a plant that works, you DO NOT try anything under production!
If something goes wrong, then
If there is a problem then tell us about and maybe we can help.
glhf
Re: [?]: Replace a 315-2PN/DP CPU
Posted: Wed Apr 03, 2013 4:31 pm
by bilbo_321
You can do it if you swap only PLCs, without changing IO modules or remote IOs .
S7-300 has no load memory and uses MMC as such load memory. All the logic and configuration is stored ONLY on MMC card, so if you plug MMC2 into PLC1 it will act as PLC2. You don't need to do any changes in NetPro or HWConfig.
THERE COULD BE ONLY ONE PROBLEM: If PLC program is locked to MMC serial number. There is PLC instruction, which reads the MMC serial. It is used mainly for software copy protection. Some Siemens communication drivers (for example Modbus drivers) check MMC serial number and doesn't work if it is not the expected serial number.
sanruku of course is right. It is dangerous to do experiments on running plant, but if you take all the precautions (for example operate emergency stops, ensure there are no people working on the machine, etc.), then it should be safe and OK.
It is your responsibility at the end.
Good luck.
Re: [?]: Replace a 315-2PN/DP CPU
Posted: Wed Apr 03, 2013 5:30 pm
by Homeroid_BL
bilbo_321,
please explain how MMC serial number could cause a problem.
If program reads MMC serial number, and program is on the same MMC?
Re: [?]: Replace a 315-2PN/DP CPU
Posted: Thu Apr 04, 2013 8:59 am
by bilbo_321
Sorry, my mistake. You are right.
It could be a problem if you upload program from one PLC (MMC) and load it on different.
It is OK if you just swap MMCs.