SI 500H


Thread Starter


Has anyone ever heard of an SI 500H or S1 500H PLC by Siemens? I have a customer who says it is over 15 years old and he wants to replace it. It says SIMATIC on it.

Thanks for your help.


Daniel Chartier

Hello Mr. Milton;
Siemens had a line of PLCs called S5, with (in those days)denominations S5-110, S5-130, S5-150; added extensions were -U(usual configuration), -F (failsafe operation) and -H(fault-tolerant, only for the S5-150). So you could have a S5-150-H PLC from Siemens on your hands. You can tell by the build of the rack: the S5-150 family had a power supply and fan mounting on the bottom of the
rack, under the CPUs and I/O cards. Quite a heavy piece of construction, easily recognized.
If this is what you have, then this brings us to the second part of the question: replacement. The S5-150-x series was replaced around 1990 by the
S5-155-x; this has been phased out in the late 1990s. Siemens now promotes the S7 family, which is hardware-incompatible with the S5. You can still buy S5-155 CPUs at a huge cost (and I mean very hefty markups!) from Siemens Spare parts; I
do not believe that you can still get parts for the S5-150-x. Your best bet would be a communication card to the I/O rack so a modern S7 CPU can talk to the I/O cards and incorporate them in its own logic. It would mean programming
the S7 with the old logic of your process, and I am not sure that the fault-tolerance of the -H system can be maintained; but that is much easier to do than getting all the hardware/software commbinations necessary to talk to the old S5s. Siemens has programs to help end-users convert (or at least finance the conversion) of S5 applications to S7. If that is the way you want
to go, I recommend you contact a Siemens Solution Provider --integrators with experience and training in these matters.

Hope this helps,
Daniel Chartier
[email protected]
Thanks for the assistance. It turns out that the customer who was looking for this info had a custom piece of equipment. Thanks again.