Rosemount 248 - Page 48

Reference Manual
00809-0100-4825, Rev BB
August 2005
Rosemount 248
A-2
Transient Protection
The Rosemount 470 prevents damage from transients induced by lightning,
welding, heavy electrical equipment, or switch gears. Refer to the Rosemount
470 Product Data Sheet (document number 00813-0100-4191) for
more information.
Temperature Limits
Operating Limit
• –40 to 185 °F (–40 to 85 °C)
Storage Limit
• –58 to 248 °F (–50 to 120 °C)
Turn-on Time
Performance within specifications in less than 5.0 seconds after power is
applied to transmitter, when damping value is set to zero seconds.
Update Rate
Less than 0.5 seconds
Custom Alarm and Saturation Levels
Custom factory configuration of alarm and saturation levels is available with
option code C1 for valid values. These values can also be configured in the
field using a HART Communicator.
Software Detected Failure Mode
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) operation. The values for standard and
NAMUR-compliant operation are as follows:
Table A-1. Operation
Parameters
Certain hardware failures, such as microprocessor failures, will always drive
the output to greater than 23 mA.
Standard
(1)
(1) Measured in milliamperes
NAMUR NE43- Compliant
(1)
Linear Output: 3.9 ≤ I ≤ 20.5 3.8 ≤ I ≤ 20.5
Fail High: 21 ≤ I ≤ 23 (default) 21 ≤ I ≤ 23 (default)
Fail Low: I ≤ 3.75 I ≤ 3.6