APG MPX Slave Sensor user manual - Manual (Page 9)

Rev. B, 4/13 MPX Series Magnetostrictive Level Sensors
9
Automation Products Group, Inc.
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• Sensor Communications
Modbus
(RS-485)
The MPX-E1 and MPX-R1 series utilizes standard Modbus RTU protocol (RS-
485). The sensor can only operate as a slave device. For more information
about Modbus RTU, please visit www.modbus.org.
The sensor will transmit at: 9600 baud, 8 bits, 1 Stop Bit, No parity (allow a
minimum delay of 300 ms between transactions).
12-24 Vdc
Out
Power Source
(14- 24 Vdc)
Sensor
RST-4100
Programming Module
Wiring
(MPX-E2, MPX-R2, MPX-E3, and MPX-R3)
To USB
Out 24V
RST-4100
Load Resistor
(100 Ω to 700 Ω)
+
−
Note: a minimum of
14 Vdc is required to
establish communications
4-20 mA
(requires RST-4100 module)
MPX-E2, MPX-R2, MPX-E3, and MPX-R3 sensor versions require the RST-4100
module and the APG Modbus software for programming.
A load resistance is required at the DC Common (GND) end of the current
loop in order to establish communications. The RST-4100 is wired in parallel
between the power source and the sensor, with the load resistance between
the “Out” leg connection and the power source ground (as shown below).