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Reference Manual
00809-0200-4728, Rev RA
Appendix A: Specifications and Reference Data
April 2015
Specifications and Reference Data
Temperature limits
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.
shows the configuration
alarm ranges.
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).
Operating limit
Storage limit
With LCD display
(1)
(1) LCD may not be readable and display updates will be slower at temperatures
below -4
°
F (-20
°
C).
–40 to 185 °F
–20 to 85 °C
–50 to 185 °F
–45 to 85 °C
Without LCD display
–40 to 185 °F
–40 to 85 °C
–60 to 248 °F
–50 to 120 °C
Standard
NAMUR- NE 43 compliant
Linear Output
3.9
≤
I
(1)
≤
20.5
(1) I = Process Variable (current output).
3.8
≤
I
≤
20.5
Fail High
21.75
≤
I
≤
23
21.5
≤
I
≤
23
Fail Low
3.5
≤
I
≤
3.75
3.5
≤
I
≤
3.6
Summary of Contents for Rosemount 644
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