how can we use the com mod mast function block?

can you share the details of how a com mod mast function block works and the parameters required?

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Amal Rank: 88

Asked 11 months ago

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COM_COM: BYTE := 1; (* port of the CPU/device, that you configured for modbus communication *)
COM_SLAVE: BYTE := 1; (* Slave Address of your slave *)
COM_TIMEOUT: WORD := 1000;
COM_FCT_WORDS: BYTE := 3;
COM_ADDR_READ_WORDS: WORD := 0; (* Start address of the register that you want to read - from slave's mapping *)
COM_READ_WORDS_NB: WORD := 10; (* number of registers that you want to read)
READ_WORDS: ARRAY [1..10] OF WORD; (* here you place the result of reading *)

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by Amal Rank: 88 on 2/14/2020 1:06:57 AM | Like (0) | Report

I am doing this program in LD. Now for a trial, I just want to see only one value.is that READ_WORDS will show the output.value from the meter are float. how I configure it?

by Amal Rank: 88 on 2/14/2020 1:09:11 AM | Like (0) | Report

also, I didn't work on the output section.

by kstoilov AKS expert

Rank: 5 on 2/14/2020 2:48:08 AM | Like (0) | Report

For one value - find start address in the slave manual and put it in COM_ADDR_READ_WORDS. For example 0 means %MW0.0 or register 0. Usually it is always used for something.
The readings you can look in the array element READ_WORDS online

by Amal Rank: 88 on 2/14/2020 3:03:38 AM | Like (0) | Report

in the manual the address value for the first one is40101 and it is float.should I do something else more other than creating this function block

by kstoilov AKS expert

Rank: 5 on 2/14/2020 1:03:12 PM | Like (1) | Report

for 40101 you should put 101 or 100 as start address. May be for FCT you have to try with 3 or 4.
For float you have to read two consequent registers - 101 and 102, put them to DINT array and use DINT_TO_REAL

by Amal Rank: 88 on 2/14/2020 8:22:17 PM | Like (0) | Report

ok sir but while giving the input of array of 0-1 DINT it shows an error that cannot convert the array of 0-1 DINT to DINT.

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kstoilov

Rank: 5

Answered 11 months ago

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Hi,
I will recommend you to use F1 - help function for the block and read the description of the parameters. It is very well documented in OnLine help. Also you can find many examples in AKS and web.
In case you have some specific question, which is not clear, you can ask here.

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kstoilov

Rank: 5

Answered 11 months ago

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how can we use the com mod mast function block?

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