Electrical Connections - Honeywell touchpoint Pro Operating Instructions Manual

MAN0923_Issue 3_04/15
14. Appendix 1 - Modbus Option

14.2.3 Electrical connections

The electrical connections are shown below:
Terminal
1
2
3
4
5
Note: The respective IN and OUT terminals are connected together internally, i.e. A1 IN is connected to
A1 OUT
14.2.4 Configuration Examples
The Modbus interface consists of two independent Modbus ports. The RS485 connections are located on
terminals TB6 and TB7 of the Control Module. For convenience, IN and OUT terminals are provided which
are connected together internally.
The diagram below gives example configurations of which the second and third offer redundancy:
14.2.5 Termination resistor
If the Touchpoint Pro is the last node in a Modbus system highway, it is necessary to connect a termination
resistor between A and B, to avoid reflections on the RS485 circuit.
For convenience, Touchpoint Pro has a set of jumpers which will switch a 120 Ω resistor across the
connection. In this case, the RS485 IN and OUT terminals are no longer connected together internally, and
the OUT terminals are floating. Only the IN terminals should be used.
Note: The default configuration for the jumpers is with the termination resistance off.
Modbus RTU Interface
TB6
A1 IN
B1 IN
A1 OUT
B1 OUT
Drain TB6
TB7
A2 IN
B2 IN
A2 OUT
B2 OUT
Drain TB7
180
Touchpoint Pro
Operating Instructions