Hardware reference guide

Modbus Plus NOM
35013379 02 October 2007 295
Front Panel
Switch
A three-position slide switch is located on the front of the unit. This switch is used to
select the comm parameter settings for the Modbus (RS-232) port. The three
options that are available, as shown in the figure below, include setting the slide
switch in the top position (ASCII), middle position (RTU), or bottom position (Valid
mem comm port parameters).
Setting the slide switch to the top position assigns ASCII functionality to the port. The
following table shows the ASCII comm port parameters, which are set and cannot
be changed.
Setting the slide switch to the middle position assigns remote terminal unit (RTU)
functionality to the port; the following RTU comm parameters are set and cannot be
changed.
Diagnostics Power Up Runtime
RAM RAM
RAM Address RAM Address
Executive Checksum Executive Checksum
Processor
Power Dissipation 4 W
Bus Current Required 750 mA max
External Power Not required for this module
Specifications
ASCII Comm Port Parameters
Baud 2,400
Parity Even
Data Bits 7
Stop Bits 1
Device Address Rear panel rotary switch setting
RTU Comm Port Parameters
Baud 9,600
Parity Even
Data Bits 8
ASCII
RTU
mem
This document provided by Barr-Thorp Electric Co., Inc. 800-473-9123 www.barr-thorp.com