7 mstr modicon ladder logic block, Using the mstr modicon ladder logic block, Mstr modicon ladder logic block -195 – Delta RMC101 User Manual
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Modbus Plus 5.3
Communications
5-195
5.3.7 MSTR Modicon Ladder Logic Block
5.3.7.1 Using the MSTR Modicon Ladder Logic Block
When using a Modicon PLC with the Modbus Plus or Modbus/TCP network, the MSTR (for
MaSTeR) ladder logic function block must be used. Before reading this topic for use with Modbus
Plus, you should understand Reading and Writing Modbus Plus Registers and Using Modbus
Plus Global Data. Before reading this topic for use with Modbus/TCP, you should understand
Using the Modicon Quantum with the RMC Ethernet Module.
For complete documentation on this function block, refer to the Modicon Ladder Logic Block
Library User Guide available from Schneider Electric. This topic uses information from the above
text and will describe the aspects of this block that apply to using it with the RMC module.
This function block takes the following form:
Inputs
There are two control inputs:
• Enable: This input must be ON for the duration of an operation
• Terminate: This input terminates the active operation when ON
You must keep the enable input on for the duration of the operation. The following two ladders
accomplish this in different ways: