Emerson Rosemount 248 Reference Manual page 35

Reference Manual
00809-0100-4825
A complete line of temperature sensors, thermowells, and accessory mounting hardware
is available from Emerson.
Set output units
The Set Output Unit command establishes the desired primary variable units. The
transmitter output can be set to one of the following engineering units:
• Degrees Celsius
• Degrees Fahrenheit
• Degrees Rankine
• Kelvin
• Ohms
• Millivolts
50/60 Hz filter
The 50/60 Hz Filter command sets the transmitter electronic filter to reject the AC power
supply frequency in the plant.
Terminal temperature
The Terminal Temp command sets the terminal temperature units to indicate the
temperature at the transmitter terminals.
Process Variable (PV) damping
The PV Damp command changes the response time of the transmitter to smooth
variations in output readings caused by rapid changes in input. Determine the damping
setting based on the necessary response time, signal stability, and other requirements of
the loop dynamics of the system. The default damping value is 5.0 seconds and can be
reset to any value between zero and 32 seconds.
The damping value chosen affects the response time of the transmitter. When it is set to
zero (or disabled), the damping function is off and the transmitter output reacts to
changes in input as quickly as the intermittent sensor algorithm allows (refer to
Intermittent
the damping value increases the transmitter response time.
With damping enabled, the transmitter outputs values according to the following
relationship.
Damping value =
At the time the damping time constant is set, the transmitter output is at 63 percent of
the input change and continues to approach the input according to the damping
equation above.
Rosemount 248 Temperature Transmitter Reference Manual
threshold) for a description of the intermittent sensor algorithm). Increasing
Configuration
May 2019
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