S7-200 Set, Reset (N Bits) where N=0 ?

mhopley · Nov 19, 2008

I am looking at a S7-200 program offline that has code that uses set & reset commands but the length is set to 0.

The online helps states that you can set or reset from 1 to 255 points.

Does anyone know what the value of 0 does? I presume nothing but I want to make sure it is not some sort of undocumented trick.

TIA

clemens · Nov 19, 2008

mhopley said:
I am looking at a S7-200 program offline that has code that uses set & reset commands but the length is set to 0.

The online helps states that you can set or reset from 1 to 255 points.

Does anyone know what the value of 0 does? I presume nothing but I want to make sure it is not some sort of undocumented trick.

TIA

This feature is not undocumented. The parameter is used to specify if there are more signals to reset.
Example: R m 30.0,2 wil reset M30.0, m30.1 and M30.2.

I hope it helps.

mhopley · Nov 19, 2008

clemens said:
This feature is not undocumented. The parameter is used to specify if there are more signals to reset.
Example: R m 30.0,2 wil reset M30.0, m30.1 and M30.2.

I hope it helps.

The way I have used this in the past is with value of 1 to set/reset 1 bit. So R M 30.0,8 resets the whole byte.

Unfortunately I do not have a PLC here to test with. Can someone confirm this is right or wrong?

clemens · Nov 19, 2008

Yes, you are right. With 0 you set or reset no bit. With 8 you set or reset 8 bits. After reading again your question I came to understand what you were really asking and I don't know.

Sorry

Nick B · Nov 19, 2008

This is allowed because the n can be a variable (example MB10).

0 does nothing.

mhopley · Nov 21, 2008

Nick B said:
This is allowed because the n can be a variable (example MB10).

0 does nothing.

Thanks Nick for clearing that up

S7-200 Set, Reset (N Bits) where N=0 ?

mhopley

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clemens

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mhopley

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clemens

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Nick B

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mhopley

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