Hi, I'm upgrading from an Allen Bradley PLC-5/40 to a Siemens S7-400.
I've been trying to find out cycle times for each but to no avail - all I can find is the I/O scan time for the AB and the bit operation times for the S7.

Would anyone know roughly what a comparable S7 version would be, performance and speed wise, to the PLC-5/40?

Thankyou.
Stevo

Don't know anything about S7, but one thing to check is number of I/O points. The 5/40 can have quite a bit of I/O. Depending on complexity of the programming, available memory could also be a huge factor.

What exactly do you mean by cycle times? In the AB the scan rate is the amout of time for the PLC to complete one scan, that is one cycle in my mind. All the I/O have been updated/read, all the logic has been evaluated, all comms. have taken place.

Yep, there is enough I/O on the 400 and I believe anything but the smallest 400 has enough memory for the program.

As for cycle time, yes, that was what I was meaning. I believe anything above the 414 series should actually be fast enough for my needs, it would just be good to find this out for definite.