Emerson Rosemount 644h, Справочное руководство

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Reference Manual
00809-0100-4728, Rev HA
December 2002
Models 644H and 644R
A-2
NAMUR Recommendations
The Model 644 meets the following NAMUR recommendations:
• NE 21 – Electromagnetic compatibility (EMC) for Process and
Laboratory Apparatus (644H only– hardware revision 26 and later)
• NE 43 – Standard of the signal level breakdown information of digital
transmitters
• NE 89 – Standard of temperature transmitters with digital signal
processing
Transient Protection
The Model 470 prevents damage from transients induced by lightning,
welding, or heavy electrical equipment. For more information, refer to the
Model 470 Product Data Sheet (document number 00813-0100-4191).
Temperature Limits
Turn-on Time
Performance within specifications in less than 5.0 seconds after power is
applied, when damping value is set to 0 seconds.
Update Time
≤ 0.5 seconds
Hardware and Software Failure Mode
The Model 644 features software driven alarm diagnostics. The independent
circuit is designed to provide backup alarm output if the microprocessor
software fails. The alarm directions (HIGH/LO) are 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 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.
The values for standard and NAMUR-compliant operation are as follows:
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 HART Communicator.
Operating Limit Storage Limit
With LCD Display –4 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 –58 to 248 °F
–50 to 120 °C
Table A-1. Operation Parameters
(1)
(1) Measured in milliamperes.
Standard NAMUR- Compliant
(2)
(2) Meets NAMUR NE 43 recommendations for breakdown information of a digital transmitter.
Linear Output: 3.9 ≤ I
(3)
≤ 20.5
(3) I = Process Variable (current output).
3.8 ≤ I ≤ 20.5
Fail High: 21
≤
I
≤
24 21
≤
I
≤
23
Fail Low: I
≤
3.75 I
≤
3.6