SMC Networks 1560 user manual Programming Considerations

Chapter 4 — Programming Considerations

Contents

4 Programming Considerations

Transferring data to/from the 1560-MBP is performed either using the standard MSTR instruction, or using the Peer Cop functionality available in some Schneider processors. (Note that Peer Cop functionality is somewhat limited. See Appendix C.) Specifically, the following functionality is supported:

MSTR Type 1 - Write data

MSTR Type 2 - Read data

MSTR Type 5 - Write Global Data

MSTR Type 6 - Get Global Data

The following sections will detail the programming requirements for each of these commands, as well as discuss speed trade- offs between the different commands. An application note detailing the configuration of a Peer Cop solution is also available in Appendix C.

4.1Writing to the 1560-MBP

4.1.1 Global Data Enabled - MSTR Type 5

If Global Data Control Mode is enabled, the 1560-MBP will look to the Host’s Global Data space for the Control and Reference values. All other values must be written by the host using the MSTR Type 1 instruction in the PLC.

The location of the Control and Reference values in the Global Data is determined by the 1560-MBP Modbus Plus address. The 1560-MBP uses the following algorithm to obtain the values:

If Modbus Plus Address < 17

Global Table Index = ( Modbus Plus Address - 1 ) * 2 else if Modbus Plus Address < 33

Global Table Index = ( Modbus Plus Address - 17 ) * 2 else if Modbus Plus Address < 49

Global Table Index = ( Modbus Plus Address - 33 ) * 2 else if Modbus Plus Address < 65

Global Table Index = ( Modbus Plus Address - 49 ) * 2

Note

The Global Data Table has a limit of 32 words, therefore there can only be 16 1560-MBP units with Global Control Enabled on one Host processor. Care must be exercised that all 16 Global Control Enabled 1560-MBP devices are in the same block of addresses.

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