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Old May 30th, 2010, 04:13 AM   #1
hagos
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EM 277 as a slave in a 315-2DP Master

Dear Folks,

I have a 315-2DP master that have several EM 277 slaves attached to it, a typical I/Q address for two EM's is as follows: Slave 1:1344-1407(32 word out/32word in)for their I/Q addresses
slave 2:1536-1599(32 word out/32word in)for their I/Q addresses

Now I want to reflect the status of one bit in slave 1 to be read in slave 2 , I tried to write a code in the 315, but the CPU doesn't accept an address of (I 1536.0 or Q 1536.0) for instance.

Waiting to get your help as usual.

Regards
Hagos
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Old May 30th, 2010, 05:03 AM   #2
JesperMP
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Thw two adresses are probably outside the proces image of the CPU.

I recommend that you read all data from each slave with SFC14 DPRD_DAT, and write all data with SFC15 DPWR_DAT.
You must set aside some memory for use in you code. Preferably a DB.
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Old May 31st, 2010, 01:06 AM   #3
hagos
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Thanks Jesper for the reply,

This is what I texpected too, but I thought it is ok when the HW configuration allowed me to enter the address I/Q 1536.

Can the SFC15/15 let the slave to put the data in a DB at the master side? If so I appreciate if you can show me how.

Best regards
Hagos
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Old May 31st, 2010, 02:56 AM   #4
JesperMP
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I suggest that you transfer the i/o data from the two slaves to one or more DBs by means of SFC14 and SFC15.
Then in code, you manipulate the i/o in the DBs.

Like this:

Read all DP slave input data with SFC14.

Do something in code.
Like:
A "DP_IO".inp.word1536.bit00
= "DP_IO".outp.word1536.bit00

Write all DP slave output data with SFC15.

An alternative if there is not so much data from each slave is to simply place the i/o inside the proces image.
Then you can simply write:
A I36.0
= Q36.0
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