20
WIRING (ALL MODELS)
Check the distance between the sensing head and the electronics module, and between the
electronics module and the instrumentation. If necessary, the sensor can be ordered with a
longer cable between the sensing head and the electronics module.
Do not extend or shorten the sensing head cable. The head and electronics module are
calibrated as a pair, and modifying the sensing head cable can affect the measurement
accuracy. Contact Calex for assistance.
The output cable from the electronics module should have an outer diameter between 3.0 and
6.5 mm, with conductors of size 28 to 18 AWG.
The terminal blocks in the electronics module may be removed from the circuit board for easy wiring.
Do not connect or disconnect the touch screen circuit board from the main circuit board while
the sensor is on.
WIRING (-BB AND -BRT MODELS)
When connecting several sensors in a single Modbus network, all of the sensors should be
connected via a junction box to a single network bus cable, running from the furthest sensor to
the Modbus Master.
Up to 247 sensors may be connected to a single Modbus network. Each sensor must have a
unique Modbus address. The Modbus address may be changed via the touch screen interface
on -BRT models, or via Modbus.
To help prevent data reflections, please ensure the cable between each sensor and the main
network bus is as short as possible. The network bus should be terminated with a resistor of
120
Ω
between the RS+ and RS- wires. The PWR- wire of the bus should be connected to the
signal ground of the Modbus Master.
MODBUS OVER SERIAL LINE (RS485)
Interface
Baud rate
9600
Format
8 data, No parity, 1 stop bit
Reply delay (ms)
20
Supported functions
Read register
0x03, 0x04
Write single register
0x06
Write multiple register
0x10
Mask write register
0x16
Read/write
0x17
