4
Field Calibration with an Accurate Adjustable Resistance Source
Note: The nominal output value for the various output ranges are designated in the
following order: (0 to 20 mA, 4 to 20 mA, 0 to 10 VDC)
1.1 Connect resistance source to the RTD input terminals using a third sense wire.
(For 2 wire sensors, short terminal #7 to terminal #8.)
1.2 Set the type and Range for the RTD or resistance used in your application. (DIP
switches #4, #6, #7 & #8). (RTD alpha = 0.00385, Range 0 shown). APPLY
OPERATING VOLTAGE and allow 45 minute warm-up period.
1.3 Set the FIELD CAL switch (#2) ON. [Output goes to -0.8 mA, 3.5 mA, or -0.4 V
nominal]
1.4 Set the input resistance to the value intended to generate the analog low endpoint
(For 2 wire sensors, add the system lead resistance to the desired value.)
1.5 Set the OUTPUT CAL switch (#1) ON. [Output stays at -0.8 mA, 3.5 mA, or -0.4
V nominal]
1.6 Adjust the input signal up until the analog output equals desired low value.[0 mA,
4 mA, or 0 V]
1.7 Set the OUTPUT CAL switch (#1) OFF. [Output increases to 22.9 mA, 22.5 mA,
or 11.5 V nominal]
1.8 Set the input resistance to the value intended to generate the analog high endpoint.
(For 2 wire sensors, add the system lead resistance to the desired value.)
1.9 Set the OUTPUT CAL switch (#1) ON. [Output decreases to 21.1 mA, 20.7 mA,
or 10.6 V nominal]
1.10 Adjust the input signal down until the output equals desired high value. [20 mA,
20 mA, or 10 V]
1.11 Set the OUTPUT CAL switch (#1) OFF.
1.12 Set the FIELD CAL switch (#2) OFF.
1.13 Disconnect the resistance source from the IRMA and connect the actual sensor to
be used in the application.
DIP SWITCH SETTINGS:
ON = 1
OFF = 0
9-32 VDC
V+
I+
VDC+
RTD(S)
POWER
RTD(-)
RTD(+)
VDC-
9
ERROR
7
8
12
10
11
6
3
4
1
5
2
V-
I-
5
1
4
3
2
8
7
6
RANGE
RANGE
OHMS/RTD
FIELD CAL
BASIC CAL
OUTPUT CAL
392
SEN UP/DN
MODEL IRMA
ERROR
POWER
VDC+
10
RTD(S)
7
V+
4
I+
1
VDC-
RTD(+)
12
11
9
8
6
5
V-
3
2
I-
POWER SUPPLY
9 to 32 VDC
VOLTAGE METER
OR
CURRENT METER
MONITORING INSTRUMENT
RTD(-)
ADJUSTABLE
RESISTANCE
SOURCE
-
+
S
Field Calibration Wiring
1.0 Field Calibration
CALIBRATION PROCEDURES
1
6
5
4
3
2
8
7
ON
1
6
5
4
3
2
8
7
ON
1
6
5
4
3
2
8
7
ON
1
6
5
4
3
2
8
7
ON
1
6
5
4
3
2
8
7
ON
1
6
5
4
3
2
8
7
ON
1
6
5
4
3
2
8
7
ON
Step 1.11
Step 1.12
Step
1
.
2
Step 1.3
Step 1.5
Step 1.7
Step 1.9
Field Calibration scales the selected output to a temperature or resistance
input. This procedure assigns an input value to the low end and an input value
to the high end. The microprocessor handles configuring the output so it is
linear to the temperature or resistance input. The Field Calibration procedure is
described below.
Note: The unit needs to have the Field Calibration completed by the operator
before normal operation. To abort this calibration and reset to the previous
settings, set the FIELD CAL switch OFF prior to the final OFF setting of the
OUTPUT CAL switch (Step 1.11) and turn off power. Wait 5 seconds and then
turn on power and the previous settings will be loaded.
RTD temperature to resistance conversion table
195.80
194.09
250
177.23
175.85
200
173.48
172.17
190
158.36
157.33
150
139.20
138.5
100
119.75
119.40
50
100.00
100.00
0
79.96
80.30
-50
59.55
60.25
-100
38.64
39.71
-150
34.38
35.53
-160
alpha
0.00392
alpha
0.00385
Temperature
°C
333.90
329.54
650
330.68
326.38
640
317.66
313.63
600
314.38
310.41
590
301.13
297.42
550
284.30
280.92
500
267.18
264.13
450
253.28
250.49
410
249.77
247.05
400
232.07
229.69
350
214.08
212.03
300
alpha
0.00392
alpha
0.00385
Temperature
°C