S5 to S7 Conversion Cross Reference

I'd simply like to know if there is a document (possibly from Siemens) where i can find the recommended replacement S7-300 CPU for a given S5-CPU.

Or if someone with experience in this jungle can help me out.

1st CPU to replace is S5-115U with 176 digital inputs and 144 digital outputs.

2nd-4th CPU to replace is S5-100U with 48 digital inputs and 24 digital outputs.


Best
Regards
Pethoek

S5/s7

Hello,

if there is only simple bit handling in the 100U i think you could use CPU312 or bigger. For the 115U you need a CPU that supports multiline structure or DP. Here i think minimum 314. But matters is the size of RAM. I don't know your program.

Exactly what type is the 115U CPU ?
Edit: And the 100U CPUs ?
Is there some kind of networking ?
What about the HMI, if any ?
Are you after the absolutely lowest cost, or the most future-proof design ?

The 115U is a 942

For all CPU, no networking, No HMI, No Nothing, Just Plain and Simple DIO's

The programs are simple, just controlling beltmotors on/off. and so on. I know lot's of timers are used in the program of the 115U, and some counters too.

The programs of the 100U there might be timers and counters used, but thats all.

The 314 and 312 CPUs mentioned by sps-concept should be more than enough for the application.

Two things though.

I really recommend to think ethernet for future projects (which includes complete rebuild of older plants). And there is probably a panel with lots of buttons and lamps for operating the system. So you might be well advised to add some kind of HMI. This will be much much more flexible, and also lower cost in the long run.
If you go along these lines, then maybe a 315-2PN/DP to replace the 115U, and IM151-8 to replace the 100Us.

If this is functionally one big plant, currently controlled by the separate CPUs, with a lot of interlocking signals going back and forth, then you might consider to have one single CPU + distributed i/o.
If you go along this line, then a 315-2PN/DP + ET200S i/o on profibus is the way to go.

1 Plant 4 locations. No need for PN/DP networking, No Need for HMI. Just replacing of 4 old PLC CPU's.

Thanks for your answer. I will recommend replacing the 115U with a S7-315 and the other 3 100U with S7-312.

I will recommend replacing the 115U with a S7-315 and the other 3 100U with S7-312.

Click to expand...

If you do not plan to use any networking, then a 315-2DP or 315-2PN/DP will be overkill. A 314 will do.
If you plan to use ethernet, be sure to specify a 315-2PN/DP, not just a 315-2DP.

Sorry, i ment, replacing the 115U with a S7-314 not 315 since it is no "plain" version of the 315.... I can understand i confused you

Its OK.

The only remaining thing you have to worry about is what i/o modules to install in the 314 racks. You probably want to reuse the existing wiring as much as possible. The maximum is 32 i/o modules in 4 racks. There are for example relay output modules with 16 channels, but then they are grouped together with a common potential on one side. If you need isolated channels, then you must accept 8 channels per module.

For the S5-115U you can replace the CPU by the VIPA IM316DP-Slave card, and this way you can keep all the wiring an I/O cards of the 115U. Then you can connect the IM316DP via Profibus to a new S7-300 CPU. This is a nice solution to make the transition.
If things go wrong, you can remove the IM316DP and install back the CPU untill you get things to work OK.