this Error is come slave block ,how to rectifier

Joshua H.

smiffy

Further investigation reveals that the are 8 configurable data areas for the Modbus_Slave block (Data_Area_Array[]). However, these are part of the instance data from the FB and are described as "Internal use only". Yet the help seems to hint that you can configure these with your own data.
How do these work? Do I use these inplace of MB_HOLD_REG input? If so, what do I do with the MB_HOLD_REG input? It would seem from the documentaion that leaving it blank will result in an error though.

It is important to note that the "Data_Area_Array[]" was not available prior to the release of TIA Portal V15. 

 

smiffy

How do you define the 4 Modbus data araes for the RTU modbus slave on the S7-1500 on TIA V15?

In Modbus, there are 4 data areas - Coils (000001 to 09998), Duscrete Inputs (10001, to 19998), Input Registers (30001 to 39998) and Holding Registers (40001 to 49998).

However, the Modbus_Slave system block only has one data area configuration input MB_HOLD_REG. From the parameters name, it implies that you can only define holding registers. However, this is kind of contradicted by the manual specifying that it supports function codes that access Modbus data types other than just holding registers.

How can 4 data areas be configured by one parameter? How do you specify the size of the data area that is accessible? Does it simply deduce this from the DB size?

 

Essentially, without the new data area feature of V15, you have no control over the definition of the coils and inputs. The coils and inputs correspond to the Q memory and I memory (respectively) of the CPU. You can only define the holding registers in M memory or data blocks.

Q: How can 4 data areas be configured by one parameter?

A: They can't. The one parameter "MB_HOLD_REG" is only to specify the memory location of the holding registers.

Q: How do you specify the size of the data area that is accessible? Does it simply deduce this from the DB size?

A: The data area size for the coils and inputs is the size of the I and Q memory of the CPU. The holding register size is the size of the memory referenced by the "MB_HOLD_REG" parameter.

Let me try to explain below. NOTE: I have inserted screen shots from an example project in TIA Portal V15. There are 2 S7-1500 CPUs in this example, one acts as a master and one acts as a slave.

The below screen shot is how I might setup my Modbus_Slave on an S7-1500 CPU. I only need to define the holding registers for the Modbus_Slave. I create an array of 1024 bytes inside a global data block that will be my slave's holding registers. Of course, 1024 bytes is 512 registers.

You can also us M memory: For a buffer in M memory, use the Any Pointer format. This is in the format P#"Bit Address" "Data Type" "Length", an example would be P#M1000.0 WORD 500.

Here are some examples from the Modbus_Master side. Hopefully the network comments will help explain what is going on.

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Split from S7-1500 Modbus_Slave defining address areas.

Hello,

pls be kind post only your question (text) normally without any added screenshots because it's hard to read your post. Add ZIP file as attachment with some possible screenshots, this is best for read and look to problems.

SATHISHANBU

this Error is come slave block ,how to rectifier

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Split from S7-1500 Modbus_Slave defining address areas.

IN SOFTWARE HELP

16#81E7: Synchronization error module and Receive_P2P

Make sure that different instances of the Receive_P2P do not access the same module.

How many configurations are there to establishing communications? Hint: There can be only one master or slave configuration per port.