User Manual

3 9 65-2649RK-HC-04 M2A Transmitter Operator’s Manual
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 m odif ied 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, th e M2A automatically returns to normal opera tion.
NOTE: If the M2A returns to norm al 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 DOW N/NO and
ENTER buttons for 5 seconds to enter Modbus Mode. Release the buttons when the
following screen appears.
2. To exit Modbus Mode, pre ss and release the DOWN/NO button. The M2A will r eturn
to no rmal ope ration.
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 th e UP /YES and
DOWN/NO buttons to adju st it to the desired setting, then press ENTER to contin ue
to the next parameter.
If the curr ently displayed parameter setting is OK, press the ENTER button to proceed
to the next parameter.
Table 9 lists the M2A Modbus Mode parameters yo u can set. Table 9 also lists the
factory set value for each para meter.
Set Up
Modbus?