65-2643RK-05-04 M2A Transmitter Operator’s Manual
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Using the M2A in a 4-wire Modbus System
Although the M2A is a 2-wire Modbus RTU device, it can be used with a 4-wire Modbus controller if the system
wiring is modified as follows:
•
Connect the controller’s TxD0 and RxD0 wires together and use this connection as the 2-wire Modbus D0
signal.
•
Connect the controller’s TxD1 and RxD1 wires together and use this connection as the 2-wire Modbus D1
signal.
•
Connect these D0 and D1 signals and the common wire from the controller to the 2-wire Modbus Network
of M2As.
Modbus Mode
Modbus Mode allows you to configure various parameters relating to the Modbus setup of the M2A. Modbus
Mode includes a 5-minute time-out feature. If you do not press a control button for 5 minutes, the M2A
automatically returns to normal operation.
NOTE:
If the M2A returns to normal operation because of a time-out, it enters a warm-up period just as it
does when it is first turned on.
1.
While in normal operation, simultaneously press and hold the DOWN/NO and ENTER buttons for 5
seconds to enter Modbus Mode. Release the buttons when the following screen appears.
2.
To exit Modbus Mode, press and release the DOWN/NO button. The M2A will return to normal operation.
To continue in Modbus Mode, press and release the UP/YES button. The current ENABLED/DISABLED
setting will appear.
3.
If you want to change the currently displayed parameter, use the UP/YES and DOWN/NO buttons to adjust
it to the desired setting, then press ENTER to continue to the next parameter.
If the currently displayed parameter setting is OK, press the ENTER button to proceed to the next parameter.
Table 9 lists the M2A Modbus Mode parameters you can set. Table 9 also lists the factory set value for each
parameter.
Set Up
Modbus?
