D12
EX-IR
Gas Transmitter with IR Smart Sensor
Dec 2019 ( 85-0004 Rev A)
70
HART Find Device
Selecting Find-Me presents a special page that remains until the master device issues a “Find Device”
command to the transmitter, at which point, line 1 of the display changes from “FIND ME ARMED” to
“DEVICE FOUND”.
Figure 78. Hart Find-Device Display
Modbus
The following applies to transmitters that have an RS232 or RS485 COM interface and the Modbus firmware option.
Modbus is a master/slave protocol that supports a single master, and up to 247 slave devices on a
common bus. The RS485 interface physically limits this number to 32 (1 master, 31 slaves), and RS232
restricts communication to a master and a single slave. Note that the 4-20mA output is fully functional
even when using the transmitter’s Modbus interface.
Modbus Menu
The Modbus Menu appears by selecting Modbus from the COM Menu (page 66).
Figure 79. Modbus Menu
Item
Description
Poll Addr
This setting controls the address to which the transmitter
responds to queries from the host (1-247, default =1).
Timeout
This setting belongs to the data-link layer of the protocol
and defines the number of character bits used to frame
Modbus RTU messages. The protocol specifies the silent
interval as 3.5 characters, which corresponds to 35 bit-
times at 10 bits per character. This setting is reserved for
future use and changing it is not recommended.
FIND ME ARMED
ESC Key to exit
a) Find Me Page
DEVICE FOUND
ESC Key to exit
b) Device Found Page