S7-300 and CFCs

ranks

I'd like to find out from which S7-300 CPU one can run CFCs.

You should be able to program any S7-300 CPU with STEP7-CFC.
Some low end S7-300s have limited memory thought and are more adequate for LAD/STL programming.

ranks

I also have FBs with the alarm_8p block. From which CPU is this supported?

ranks

I'd like to find out from which S7-300 CPU one can run CFCs. I also have FBs with the alarm_8p block. From which CPU is this supported?

1. S7 300
You can only implement the Interrupt_S and Interrupt_SQ in the CPU 300s starting with CPU S7-314. The S7-312 and S7-313 cannot process this block.

Difference between the blocks:
The Interrupt_S cannot be acknowledged if the interrupt has already gone, i.e. there is a limit to the number of unacknowledged messages triggered by a CPU:

• S7-314: 40 unacknowledged messages
• S7-315: 50 unacknowledged messages

This is only a guideline. Message might well be lost earlier on if the messages are sent to quickly one after the other. The return value RET_VAL then returns 8082.

• S7-412: 50 unacknowledged messages
• S7-413: 70 unacknowledged messages
• S7-414: 100 unacknowledged messages
• S7-416: 200 unacknowledged messages