5.0 CALIBRATION
The 501
is normally delivered configured for 4-20 mA = 0 - 850°C.
5.1
TOOLS AND EQUIPMENT
#1 Phillips
screwdriver
Small flathead screwdriver for potentiometer adjustment
One 4 1/2 digital ammeter
Fixed or variable DC power supply or battery (range of 12-30
V dc)
Decade resistor box (Model 1433T General Radio or equivalent)
5.2 CALIBRATION
USING AMBIENT TEMPERATURE
Figure 5-1. Calibration Setup
5.2
CALIBRATION PROCEDURE
Refer to Figure 5-1 (Calibration flowchart) and familiarize yourself
with the general procedure to be followed.
- Refer
to Figure 5-1. Remove the four Phillips-head screws from the
case top, and set aside the plastic barrier cover. Lift out
the electronics assembly (attached to the case lid).
- Setting
aside the case and sealing gasket, pull out the two sealing
plugs which cover the Span and Zero potentiometers (pots).
Adjust the Span pot to about midway point. (For a 15-turn
pot, adjust counter-clockwise approximately 20 turns to reach
the farthest right possible. Then begin turning it clockwise
3 turns to engage and another 7.5 turns to reach midpoint.)
- Attach
the resistor box to the 501 between the + (EXCITATION) and
- (EXCITATION) terminals (use the - SENSE lead for the 3-wire
configuration). If a 3-wire configuration is not desired,
- SENSE and - EXCITATION should be connected together at the
terminal.
- From
the 501 output terminals, connect the + terminal to the +
terminal of a 12 to 30 V dc power supply or battery and the
- terminal to the + terminal of an ammeter. Close the 4-20
mA loop by connecting the - terminal of the ammeter to the
- terminal of the power source.
- Refer
to Table 5-2 for temperature ranges or Table 5-3 for ohm ranges
obtained with Zero and Span jumpers. Turn the 501 so that
the jumper pin-forest is in view (Figure 5-3), and place the
push-on jumpers in the positions chosen to yield the desired
Zero and Span ranges.
NOTE: After
jumper installation, reinstall the electronic assembly in the
case for better calibration stability.
- Turn
on the power supply. Set the resistor box to the ohms corresponding
to the desired LO temperature or ohms (Zero) from Table 5-1
or Table 5-3, and adjust the Zero pot for 4.00 mA output current.
- Set the
resistor box source to the ohms corresponding to the desired
HI temperature or ohms from Table 5-1 or Table 5-3 and read
the Temporary Output Current, designated
TOC (normally not equal to 20 mA).
- Calculate:
16 x TOC / (TOC - 4) = CFS (Current Full
Scale) milliamperes. (Generally, CFS will also not
be equal to 20.00 mA.)
- Adjust
the Span to display the CFS output on the milliammeter.
- Now readjust
the Zero so that the output reads 20.00 mA.
- Set the
resistor box back to LO temp ohms. If the output current is
not 4.00 mA, retrim starting at Item 7, above.
- When
calibrated, turn off the power supply, remove wires, and replace
pot sealing plugs. Using the four screws, secure the transmitter
in the case with a firmly compressed (but not flattened) gasket
for a good seal.
EXAMPLE
FOR OHMS:
Ohms range: 200 ohms = 4 mA, 450 ohms = 20 mA
- Calculate
the Span.
Span = ohms (20 mA) - ohms (4 mA)
Span = 450 - 200 = 250 ohms
- Refer
to the top row of Table 5-3 to find the proper Span jumper,
in this case "E" and "H."
- Using
the column labeled "Min Res for 4 mA" in Table 5-3, find the
required Zero jumpers for the selected Span. If the resistance
corresponding to the 4 mA is between two Zero jumper readings,
select the Zero jumper with the smaller reading, in this case
"B" and "D." The additional Zero suppression will be obtained
by the Zero
Calibrate:
-
| NOTE:
Steps 1 through 8 are optional as they are meant to
reduce calibration time by calculating the offset caused
by the interaction between the Zero and Span pot.
|
Set SPOT
to about midpoint.
- Set the
resistor box resistance to 200 ohm .
- Adjust
the Zero pot to 4.00 mA.
- Set the
resistor box to 450 ohm.
- Read
the current designated TOC.
- Calculate
CFS = 16 x TOC : (TOC - 4) mA.
- Adjust
Span pot to obtain CFS.
- Adjust
the Zero pot to obtain 20.00 mA current.
- Set
resistor box resistance to 200 ohm .
- If the
output is not 4.00 mA, readjust the Zero pot.
- Set the
resistor box to 450 ohm .
- If the
output is not 20.00 mA, readjust the Span pot.
- Repeat
steps 9 through 12 until 4.00 and 20.00 mA are obtained for
the corresponding 200 and 450 ohm
EXAMPLE
FOR TEMPERATURE:
| Temperature
Range |
= -200
to 400°C |
Zero
Jumper |
None |
Table
5-2 |
| Base
Temperature |
= -200°C |
Span
Jumper |
EH |
Table
5-2 |
| Top
Temperature |
= 400°C |
Base
Temp |
18.49
ohm |
Table
5-1 |
|
|
Top
Temp (Max) |
247.04 |
Table
5-1 |
Calibrate:
-
| NOTE:
For specific values not given in Table 5-1, interpolation
may be used. |
Set Span
pot to about midpoint.
- Set resistor
box resistance to 18.49 ohm.
- Adjust
Zero pot to 4.00 mA.
- Set resistor
box resistance to 247.04 ohm.
- Read
current, designated TOC.
- Calculate
CFS = 16 x TOC : (TOC - 4) mA.
- Adjust
Span pot to obtain CFS.
- Adjust
Zero pot to obtain 20.00 mA current.
- Set test
resistance to 18.49 ohm.
- If the
output is not 4.00 mA, retrim starting at Item 2 above
Figure 5-2. Calibration Flowchart
|
°C
|
Ohms
|
°C
|
|
Ohms
|
°C
|
Ohms
|
|
-200
|
18.49
|
150
|
|
157.31
|
500
|
289.90
|
|
-190
|
22.80
|
160
|
|
161.04
|
510
|
284.22
|
|
-180
|
27.08
|
170
|
|
164.76
|
520
|
287.53
|
|
-170
|
31.32
|
180
|
|
168.46
|
530
|
290.83
|
|
-160
|
35.53
|
190
|
|
172.16
|
540
|
294.11
|
|
-150
|
39.71
|
200
|
|
175.84
|
550
|
297.39
|
|
-140
|
43.87
|
210
|
|
179.51
|
560
|
300.65
|
|
-130
|
48.00
|
220
|
|
183.17
|
570
|
303.91
|
|
-120
|
52.11
|
230
|
|
186.82
|
580
|
307.15
|
|
-110
|
56.19
|
240
|
|
190.45
|
590
|
310.38
|
|
-100
|
60.25
|
250
|
|
194.07
|
600
|
313.59
|
|
-
90
|
64.30
|
260
|
|
197.69
|
610
|
316.80
|
|
-
80
|
68.33
|
270
|
|
201.29
|
620
|
319.99
|
|
-
70
|
72.33
|
280
|
|
204.88
|
630
|
323.18
|
|
-
60
|
76.33
|
290
|
|
208.45
|
640
|
326.35
|
|
-
50
|
80.31
|
300
|
|
212.02
|
650
|
329.51
|
|
-
40
|
84.27
|
310
|
|
215.57
|
660
|
332.66
|
|
-
30
|
88.22
|
320
|
|
219.12
|
670
|
335.79
|
|
-
20
|
92.16
|
330
|
|
222.65
|
680
|
338.92
|
|
-
10
|
96.09
|
340
|
|
226.17
|
690
|
342.03
|
|
0
|
100.00
|
350
|
|
229.67
|
700
|
345.13
|
|
10
|
103.90
|
360
|
|
233.17
|
710
|
348.22
|
|
20
|
107.79
|
370
|
|
236.65
|
720
|
351.30
|
|
30
|
111.67
|
380
|
|
240.13
|
730
|
354.37
|
|
40
|
115.54
|
390
|
|
243.59
|
740
|
357.42
|
|
50
|
119.40
|
400
|
|
247.04
|
750
|
360.47
|
|
60
|
123.24
|
410
|
|
250.48
|
760
|
363.50
|
|
70
|
127.07
|
420
|
|
253.90
|
770
|
366.52
|
|
80
|
130.89
|
430
|
|
257.32
|
780
|
369.53
|
|
90
|
134.70
|
440
|
|
260.72
|
790
|
372.52
|
|
100
|
138.50
|
450
|
|
264.11
|
800
|
375.51
|
|
110
|
142.29
|
460
|
|
267.49
|
810
|
378.48
|
|
120
|
146.06
|
470
|
|
270.86
|
820
|
381.45
|
|
130
|
149.82
|
480
|
|
274.22
|
830
|
384.40
|
|
140
|
153.58
|
490
|
|
277.56
|
840
|
387.34
|
|
|
|
|
|
|
850
|
390.26
|
Table
5-1. DIN 43760 Pt-100 Resistance
5.3 PIN ASSIGNMENTS (Jumper
Pin-forest P1)
Figure 5-3. Jumper Diagram
NOTE: Always install 2 span jumpers.
|
Jumper
Function
|
P1 Pins Used
|
|
'A'
Zero
|
1
and 2
|
|
'B'
Zero
|
3
and 4
|
|
'C'
Zero
|
5
and 6
|
|
'D'
Zero
|
7
and 8
|
|
'E'
Span
|
11
and 12
|
|
'F'
Span
|
9
and 11
|
|
'G'
Span
|
13
and 14
|
|
'H'
Span
|
14
and 16
|
| NOTE: P1
connector pins 10, 15, 17, 18, 19, and 29 are used solely
for computerized testing by the factory. |
|
|
| |
Span Jumper
F,H 100 to 300°C Span
|
Span Jumper
F,G 300 to 500°C Span
|
Span Jumper
E,H 600 to 800°C Span
|
Span Jumper
E,G 800 to 1050°C Span
|
|
Zero
Jumper
|
Base Temp
|
Min Temp
|
Max Temp
|
Base Temp
|
Min
Temp
|
Max Temp
|
Base Temp
|
Min
Temp
|
Max Temp
|
Base Temp
|
Min
Temp
|
Max Temp
|
| No Z-Jumper |
|
|
|
|
|
|
-200
|
380
|
645
|
-200
|
675
|
850
|
|
D
|
-200
|
-135
|
100
|
-200
|
115
|
365
|
-190
|
390
|
660
|
-145
|
745
|
850
|
|
C
|
-170
|
-105
|
130
|
-125
|
195
|
455
|
- 70
|
535
|
820
|
|
|
|
|
CD
|
- 65
|
5
|
245
|
- 15
|
315
|
590
|
40
|
670
|
850
|
|
|
|
|
B
|
35
|
105
|
355
|
85
|
430
|
710
|
140
|
795
|
850
|
|
|
|
|
B D
|
130
|
205
|
460
|
180
|
535
|
830
|
|
|
|
|
|
|
|
BC
|
220
|
295
|
565
|
270
|
635
|
850
|
|
|
|
|
|
|
|
BCD
|
305
|
380
|
660
|
360
|
740
|
850
|
|
|
|
|
|
|
|
A
|
385
|
465
|
750
|
440
|
830
|
850
|
|
|
|
|
|
|
|
A D
|
465
|
545
|
840
|
|
|
|
|
|
|
|
|
|
|
A C
|
540
|
625
|
850
|
|
|
|
|
|
|
|
|
|
|
A CD
|
610
|
695
|
850
|
|
|
|
|
|
|
|
|
|
|
AB
|
680
|
770
|
850
|
|
|
|
|
|
|
|
|
|
|
AB D
|
745
|
835
|
850
|
|
|
|
|
|
|
|
|
|
Table
5-2. Span Ranges In Degrees Celsius Obtained
with Jumpers
NOTE: The 501 has a slight variation in the input offset
of the opamp. If the selected range cannot be obtained with the
jumpers designated in Table 5-1, move to the previous or next
jumper and range selection.
NOTE: Store the unused jumpers between the bottom connector
pins and the printed-circuit board as shown in Figure 5-3.
|
|
|
| |
Span Jumper
F,H 24 to
115 ohm Span
|
Span Jumper
F,G 116 to 208 ohm Span
|
Span Jumper
E,H 209 to
301ohm Span
|
Span Jumper
E,G 301 to
393 ohm Span
|
|
Zero
Jumper
|
Min* Res
for 4 mA
|
Min Res
for 20mA
|
Max Res
for 20mA
|
Min* Res
for 4 mA
|
Min Res
for 20mA
|
Max Res
for 20mA
|
Min* Res
for 4 mA
|
Min Res
for 20mA
|
Max Res
for 20mA
|
Min* Res
for 4 mA
|
Min Res
for 20mA
|
Max Res
for 20mA
|
|
No Z-Jumper
|
|
|
|
0
|
116
|
208
|
0
|
209
|
301
|
0
|
301
|
393
|
|
D
|
0
|
24
|
115
|
10
|
126
|
218
|
30
|
239
|
331
|
47
|
348
|
440
|
|
C
|
40
|
64
|
155
|
59
|
175
|
267
|
77
|
286
|
378
|
95
|
396
|
488
|
|
CD
|
83
|
107
|
198
|
102
|
218
|
310
|
120
|
329
|
421
|
138
|
439
|
531
|
|
B
|
123
|
147
|
238
|
142
|
258
|
350
|
160
|
369
|
461
|
178
|
479
|
571
|
|
BD
|
160
|
184
|
275
|
178
|
294
|
386
|
196
|
405
|
497
|
214
|
515
|
607
|
|
BC
|
192
|
216
|
307
|
211
|
327
|
419
|
230
|
439
|
531
|
247
|
548
|
640
|
|
BCD
|
223
|
247
|
338
|
242
|
358
|
450
|
260
|
469
|
561
|
278
|
579
|
671
|
|
A
|
252
|
276
|
367
|
270
|
386
|
478
|
288
|
497
|
589
|
307
|
608
|
700
|
|
AD
|
278
|
302
|
393
|
297
|
413
|
505
|
315
|
524
|
616
|
333
|
634
|
726
|
|
AC
|
303
|
327
|
418
|
321
|
437
|
529
|
339
|
548
|
640
|
357
|
658
|
750
|
|
ACD
|
325
|
349
|
440
|
344
|
460
|
552
|
362
|
571
|
663
|
380
|
681
|
773
|
|
AB
|
347
|
371
|
462
|
366
|
482
|
574
|
384
|
593
|
685
|
402
|
703
|
795
|
|
ABD
|
367
|
391
|
482
|
386
|
502
|
594
|
404
|
613
|
705
|
422
|
723
|
815
|
|
ABC
|
386
|
410
|
501
|
405
|
521
|
613
|
423
|
632
|
724
|
441
|
742
|
834
|
|
ABCD
|
404
|
428
|
519
|
423
|
539
|
631
|
440
|
649
|
741
|
459
|
760
|
852
|
| *
Maximum for 4 mA is the minimum for the next higher range. |
Table
5-3. Span Ranges In Ohms Obtained with
Jumpers
NOTE: The 501 has a slight variation in the input offset
of the opamp. If the selected range cannot be obtained with the
jumpers designated in Table 5-1, move to the previous or next
jumper and range selection.
NOTE: Store the unused jumpers between the bottom connector
pins and the printed-circuit board as shown in Figure 5-3.
|
|
