The Modbus Module 3-9900.270-MX allows the Signet 9900 SmartPro
®
Transmitter to
connect to a Modbus master compatible device. The Modbus Module supports RTU or
ASCII modes over serial RS485 communication links.
The Modbus Module has an internal programmable network termination for the
communication link enabled by Modbus command.
English
*3-9900.270.090*
3-9900.270.090 Rev 4 08/19
Signet 9900 Modbus Module
Installation and Programming
•
Modbus RTU and ASCII modes, RTU is Default Mode.
•
1200, 2400, 4800, 9600, 19200. 38400, 57600, and 115200 Baud rates,
19200 is default Baud rate
•
Parity can be selected as Even, Odd, or None, Even is default Parity
•
Modbus Address 1 to 247, 34 is default Modbus Address
•
Data Bits, automatically selected based on Mode. RTU Mode 8 Data bits,
ASCII Mode 7 Data bits.
•
Stop Bits, automatically selected based on Mode, RTU Mode 1 Stop bit,
ASCII Mode 2 Stop bits.
•
Power 12 to 24 VDC Nominal 10.6 to 32 VDC max regulated.
Specifi cations
System Overview
Installation
If the 9900 Base Unit will be mounted in a panel, plug-in modules may be installed either
before or after the base unit is mounted.
If the 9900 Base Unit will be mounted using the accessory wall mount kit (3-9900.392), install
plug-in modules fi rst.
If the Direct Conductivity/Resistivity Module or Current Loop Module will be included in your
unit, install the Modbus module fi rst and then install Conductivity/Resistivity Module over the
Modbus Module.
To install the Modbus module, carefully align the module pins into its plug (see illustration)
and push the module straight in until the tabs on the bottom edge snap into place.
To uninstall, squeeze tabs, grasp the module and pull straight out.
Modbus Module
Modb
us Mo
dule
DC P
ower
DC P
ower
Loop V
oltage
Loop
Volta
ge
Description
Important! Do not exceed 32 VDC
or permanent damage to the
Modbus Module will occur.
Start Up Communication Parameters
The Modbus communication parameters
for 9900 Gen 1 through Gen 4 transmitters
are set via Modbus. The Modbus module
is shipped from the factory, and can
be reset in the fi eld, with the following
communication parameters. See the
Communication Setting Programming fl ow
chart below.
Setting
Default
Value
Modbus Address
34
Modbus Network Termination Off
Modbus Mode
RTU
Baud Rate
19200
Parity
Even
Endian
Big
Start Up Communication Parameters
