Emerson Rosemount 644, Reference Manual

Page: 30 / 182

20
Reference Manual
00809-0200-4728, Rev RA
Section 2: Configuration
April 2015
Configuration
2.7 Configure dual sensor options
Dual-sensor configuration deals with the functions that can be used with a transmitter ordered
with Dual Sensor inputs. In the Rosemount 644 these functions include:

Differential Temperature

Average Temperature

Hot Backup and Sensor Drift Alert Diagnostics (requires option code DC)
– First Good Temperature (requires options S and DC, or options D and DC)
2.7.1 Differential temperature configuration
The 644 ordered and configured for dual-sensors can accept any two inputs then display the
differential temperature between them. Use the following procedures to configure the
transmitter to measure differential temperature.
Note
This procedure assumes the Differential Temperature is a calculated output of the device but
does not re-assign it as the Primary Variable. If it desired for Differential to be the transmitter’s
primary variable see Section 2.6.1 Mapping the HART Variables to set it to PV.
Differential temperature configuration with Field
Communicator
From the HOME screen, enter the Fast Key sequence.
Differential temperature configuration with AMS Device
Manager
1. Right click on the device and select Configure .
2. In the left navigation pane choose Manual Setup .
3. On the Calculated Output Tab find the Differential Temperature group box.
4. Select Units and Damping settings then select Apply when complete.
Differential Temperature configuration with LOI
To configure the Differential Temperature on the LOI, the Units and Damping values must be set
separately. Reference
Figure 2-7 and Figure 2-8 below for where to find these in the menu.
Device Dashboard Fast Keys
2, 2, 3, 1