Addressing a marker bit with Citect?

Hi

I had a problem yesterday addressing a Data Word with Citect. The format need was Dxxx:zzz.bit
Where the xxx was the data block ie 010 (DB10)
and zzz was the word ie. 001 (word 1).
Bit is obviously the bit you are addressing in the word.

Does anyone know how to address a marker bit within the PLC.

I've tried M10.0, M10:0, M010.0, F10.0, F010:0 etc but I still get errors.

Any ideas?

Cheers

JT

PS. Its an S5 115U PLC... (forgot to mention that)

Johnny T,

Do you mean you cannot declare it as a variable tag in citect?

Lancer

Yes. I'm trying to declare it as a variable tag of the type 'digital'. I want to know how to address a flag bit.eg. F10.0 in the S5 PLC.

How would I write that in the address part of the tag in Citect.

Many thanks

JT

Check what the Citect driver can read in the PLC. Citect is quite often set up to read only certain memory areas. Depends on how old/new the driver is and whether the PLC manufacturer has added/changed I/O addressing in the PLC.

Is it a compile error? If so, post the message and details of the PLC and driver version etc.

Johnny TI have not worked with S5 PLC so I dont know
what special functions or ladder operators you
have at your disposal, but you may be able to
do a bit pic function, or move word to coil memory,
or word and(WAND), so you can isolate the bit into
a coventional memory address within the PLC
that citect can read.

Hi,

You cannot address Flags, Flag Byte or Flag Word in S5-115 with citect. The easiest way to read flag info is to transfer the FY (Flag Byte) into a Data Block Byte and have citect read the bit out of the Data Block. This seems very long winded, but it is the only way citect can read data from a 115.

Hope this helps you.

Andrew Butcher

Many thanks for your replies.

I didn't realise that it couldn't read a flag from S5.

I'll have to do some changes to the S5 software then and transfer the relevant flag bits to words in a data block and then read the word via citect...

Cheers

JT