S7 Function Block

Hi
I have created a FB with multiple instance capability and assigned it two instances DB. For example FB2,DB2 and FB2,BD4. Every FB has its own actual parameters and had prefect operation when call it alone. There is a problem with FBs when they called, they are not functioning independently.
Please tell me how I can make each FB work independently.

If you want proper guiding you must post the code.
Kalle

S7 fb

Thank you for prompt reply.

In attached please find the FB code.

Regards.
Honarvaran

The code you have posted only contains one call to FB2. It also contains two calls to FB4 which is not in the project. Please post code that we can run to attempt to replicate your problem.

FB2 contains the erroneous use of temp variables for edge detection storage - convert these to STAT varables.
Similarly, AM_INS is a temp variable that is not written to all of the time - convert to a STAT variable.

OUT_INS is a temp that gets used in N/W 10 but is written in N/W 28

Suggest you convert all your temp variables to STAT variables and start again.

Temp variables are not remembered between calls but are stored on a stack. If you call the FB once, the stack may remain intact (depending on what else is called) and the temps will be remembered between calls. If you call the FB twice then the temps written by the first call will be used/overwritten by the second call.

Hi
I want to thank you for sending me the answer and guide me. I replace the TEMP variable to STAT and FB works properly. But when can we use TEMP variable in function block exactly?

Sincerely,
Honarvaran.

honar said:

Hi
But when can we use TEMP variable in function block exactly?

Sincerely,
Honarvaran.

Click to expand...

A TEMP does not store values between the FB calls. So eiter don't use TEMP or only as intermediate store. In practice does this mean that a TEMP is not valid until it is assigned using S, R, =, T, (and destination for BLKMOVE, Receive-functions...)

The TEMP variables (= Local variables) is a memory stack that is open for all user programs. When a block is called, the local stack pointer is preset to the first free area - and you will never know where it is - unless you have only one call from OB1 (or OB35 or another system OB) - then you'll get the same preset each time.

You can search this forum for more info on this never ending TEMP story.

Kalle

Thanks