Configure Modbus/Rs-485 Communications - Emerson Micro Motion 2500 Configuration And Use Manual

Table 6-29: HART variables and transmitter outputs
HART variable
Tertiary Variable (TV)
Quaternary Variable (QV)
6.7.2

Configure Modbus/RS-485 communications

ProLink III
Field Communicator Configure > Manual Setup > Inputs/Outputs > Communications > Set Up RS-485 Port
Overview
Modbus/RS-485 communications parameters control Modbus communication with the
transmitter's RS-485 terminals.
Procedure
1.
2.
3.
4.
5.
Configuration and Use Manual
Reported via
Frequency Output (if
present on your transmitter)
Not associated with an out-
put
Device Tools > Configuration > Communications > RS-485 Terminals
Set Disable Modbus ASCII as desired.
Support for Modbus ASCII limits the set of addresses that are available for the
transmitter's Modbus address.
Modbus ASCII support
Disabled
Enabled
Set Protocol to match the protocol used by your Modbus/RS-485 host.
Option
Modbus RTU (default)
Modbus ASCII
If support for Modbus ASCII is disabled, you must use Modbus RTU.
Set Modbus Address to a unique value on the network.
Set Parity, Stop Bits, and Baud Rate as appropriate for your network.
Set Floating-Point Byte Order to match the byte order used by your Modbus host.
Integrate the meter with the control system
(continued)
Comments
If one assignment is changed, the other is changed auto-
matically, and vice versa. If your transmitter does not have
a Frequency Output, the TV must be configured directly,
and the value of the TV is available only via digital commu-
nications.
The QV must be configured directly, and the value of the
QV is available only via digital communications.
Available Modbus addresses
1–127, excluding 111 (111 is reserved to the service port)
1–15, 32–47, 64–79, and 96–110
Description
8–bit communications
7–bit communications
109