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These
Digital Panel Meter (DPM) models provide highly accurate, stable, and
repeatable temperature indication for signals from 100-Ohm Platinum
Resistance Temperature Detectors (RTD’s) with DIN "alpha" of 0.00385
or ANSI "alpha" of 0.003925. The
model-numbering system is given in the Specifications
table, below.
RTD
range and resolution (1° or 0.1°) are selectable from the front panel or
via special commands issued over the optional serial
interface. Data display
in units of degrees Kelvin or Rankine can be selected by offsetting the
Celsius or Fahrenheit range, respectively.
Open
sensor indication is standard, and may be set to indicate either upscale
or downscale.
RTD
excitation of 0.2 mA is provided by the meter, and is monitored to make
ratiometric corrections for excitation-supply variations.
RTD
connections can be of the 2-, 3-, or 4-wire type, with appropriate
compensation for load resistance of the sensor.
Thus, in a 2-wire hookup, the meter senses the voltage drop across
the 100-Ω RTD and both lead wires.
The effect of the lead wires can be measured and subtracted by
shorting out the RTD during meter setup.
For 3- and 4-wire connections, the meter senses the voltage drop
across the 100-Ω RTD and both lead wires, as well as the voltage
drop across the RTD and one lead wire. This allows it to determine the effect of one lead wire and
mathematically subtract the effect of both lead wires.
All
ranges for all temperature sensor types are digitally calibrated at the
factory to IEC or NIST standards, thus eliminating the need to recalibrate
in the field for potentiometer-related drift errors.
As
with all 2000 Series DPM's, the peak value of the input signal is
automatically captured and may be displayed via front-panel push
button or a control signal received at the rear connector (since the last
meter reset). Data readings and outputs can be separately selected
to be either filtered or unfiltered.
With
the optional Analog Output Board, these
meters can serve as superb, isolated 4-20 mA transmitters. The
analog output is scaled to the display, which is linearized to °C or °F
and is exceptionally accurate. The analog output tracks the high
read rate of the meter (up to 56 readings per second at 60-Hz
power). Fast update rates are beneficial in many closed-loop and PID
control applications.
With
the optional Dual Contact or Solid-State
Relay Board, a temperature meter can serve as an extremely fast and
accurate ON/OFF controller for closed-loop temperature control, or as a
supervisory process monitor, providing alarms or shutoffs when the process
exceeds normal limits.
Platinum
RTD Meter Specifications [Top
]
(Click
here for 2000 Series General Specifications)
|
|
Model
Number
|
RTD Type
|
Range
|
Conformity
Error
at 25° C
|
|
2118-1
|
DIN*
|
-202° C to +850° C
|
0.01% of full scale ±
0.03° C
|
|
2118-2
|
DIN*
|
-331° F to +1562° F
|
0.01% of full scale ±
0.05° F
|
|
2119-1
|
ANSI**
|
-202° C to +631° C
|
0.01% of full scale ±
0.04° C
|
|
2119-2
|
ANSI**
|
-331° F to +1168° F
|
0.01% of full scale ±
0.07° F
|
|
All RTD
Models
|
|
Calibration,
DIN
|
IEC
751 (IPTS-68)
|
|
Calibration,
ANSI
|
NIST
Monograph 126
|
|
Configuration
|
2-,
3-, or 4-wire connection
|
|
Excitation
Current |
0.2 mA |
|
Span
Temperature Coefficient |
±0.003% of
reading/°C |
|
Zero
Temperature Coefficient |
±0.03 deg/deg |
|
Sensor
Lead Resistance Temperature Coefficient Per Conductor |
|
2-Wire |
10 mdeg/Ω/deg
up to 10 Ω |
|
3-
and 4-Wire |
10 μdeg/Ω/deg
up to 100 Ω |
|
Overvoltage
Protection |
125 VAC |
|
Normal-Mode
Rejection at 50/60 Hz |
80 dB plus
selectable digital filter from 80 ms to 9.6 s time constant |
|
Common-Mode
Rejection from DC to 60 Hz |
120 dB with 500
Ω imbalance |
|
Common-Mode
Voltage from DC to 60 Hz |
250 VAC from
power and earth ground |
|
Open
Sensor Indication |
Flashes full-scale |
|
* α =
0.00385 ** α = 0.003925 |
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