Emerson Rosemount 644 Reference Manual page 134

Appendix A: Specifications and Reference Data
April 2015
Temperature limits
With LCD display
Without LCD display
(1) LCD may not be readable and display updates will be slower at temperatures
below -4
Hardware and software failure mode
The 644 features software driven alarm diagnostics and an independent circuit which is
designed to provide backup alarm output if the microprocessor software fails. The alarm
direction (HI/LO) is user-selectable using the failure mode switch. If failure occurs, the position
of the switch determines the direction in which the output is driven (HI or LO). The switch feeds
into the digital-to-analog (D/A) converter, which drives the proper alarm output even if the
microprocessor fails. The values at which the transmitter software drives its output in failure
mode depends on whether it is configured to standard, custom, or NAMUR-compliant (NAMUR
recommendation NE 43, June 1997) operation.
alarm ranges.
Linear Output
Fail High
Fail Low
(1) I = Process Variable (current output).
Custom alarm and saturation level
Custom factory configuration of alarm and saturation level is available with option code C1 for
valid values. These values can also be configured in the field using a Field Communicator.
Turn-on time
Performance within specifications in less than 5.0 seconds after power is applied, when
damping value is set to 0 seconds.
External transient protection
The Rosemount 470 prevents damage from transients induced by lightning, welding, or heavy
electrical equipment. For more information, refer to the 470 Product Data Sheet (document
number 00813-0100-4191).
124
Operating limit
(1)
–40 to 185 °F
–20 to 85 °C
–40 to 185 °F
–40 to 85 °C
° °
F (-20 C).
Standard
3.9 ≤ I ≤ 20.5
(1)
21.75 ≤ I ≤ 23
3.5 ≤ I ≤ 3.75
Storage limit
–50 to 185 °F
–45 to 85 °C
–60 to 248 °F
–50 to 120 °C
Table A-1 on page 97
NAMUR- NE 43 compliant
3.8 ≤ I ≤ 20.5
21.5 ≤ I ≤ 23
3.5 ≤ I ≤ 3.6
Specifications and Reference Data
Reference Manual
00809-0200-4728, Rev RA
shows the configuration