Calibration
The calibration of the SM815 is accomplished by first
setting DIP switch positions to the proper thermocouple
type and input range and then by calibrating the unit using
the span and zero potentiometers.
To calibrate the SM815 follow the procedure below:
1) Select the temperature range and thermocouple type.
NOTE that the top of the range can be from 4 to 64 mV
above the bottom of the range. The bottom of the range
is always 0 mV (or °C) ±25% of the millivolt span.
2) If you are calibrating using an ice bath and millivolt
source, find the millivolt values in a thermocouple table
corresponding to the top and bottom of your temperature
range. For example, for type J, 60 to 200°F, the millivolt
input will be 0.791 to 4.906 mV. If you are calibrating
using a thermocouple calibrator/simulator the above step
is not necessary. This is because the output of the
calibrator is given directly in units of temperature rather
than in millivolts. NOTE that the output of the SM815 is
linear with respect to the millivolt input and does not
correct for the nonlinearity of the thermocouple wire.3)
Reference table 1 and set the DIP switch positions for the
required thermocouple type and input span. Reference
table 3 for voltage inputs.
4) Set the calibration source to the bottom of the input
range and adjust the zero pot for an output of 4 mA.
5) Set the calibration source to the top of the input range
and adjust the span pot for an output of 20 mA.
6) Repeat steps 4 and 5 until the output readings are
exactly 4 and 20 milliamps.
MILLIVOLT SPAN
4 to 8
8 to 16
12 to 24
16 to 32
20 to 40
24 to 48
28 to 56
32 to 64
SWITCH 4
ON
OFF
ON
OFF
ON
OFF
ON
OFF
SWITCH 5
ON
ON
OFF
OFF
ON
ON
OFF
OFF
SWITCH 6
ON
ON
ON
ON
OFF
OFF
OFF
OFF
TEMPERATURE SPAN
°C
80 -150
150-290
220-420
290-600
370-710
420-760
TYPE J
°F
140 -270
270-530
400-790
530-1050
560-1320
790-1390
°C
100-200
200-390
290-580
390-770
480-970
580-1180
670-1370
TYPE K
°F
175-355
355-705
530-1045
705-1385
875-1740
1045-2115
1210-2500
°C
95-175
175-320
250-400
TYPE T
°F
175-320
320-585
460-750
°C
65-125
125-235
180-325
235-440
285-535
325-635
385-735
435-835
TYPE E
°F
120-230
230-430
335-615
430-795
525-975
615-1155
705-1330
795-1515
°C
450-800
800-1400
1115-1700
TYPE R
°F
840-1470
1470-2540
2025-3100
°C
480-860
860-1535
1200-1760
TYPE S
°F
875-1565
1565-2785
2190-3210
Table 1. Switch settings for millivolt and temperature spans (see notes)
TYPE J
TYPE K
TYPE T
TYPE E
TYPE R
TYPE S
SWITCH 1
ON
OFF
OFF
OFF
OFF
OFF
SWITCH 2
OFF
ON
ON
OFF
OFF
OFF
SWITCH 3
OFF
OFF
OFF
OFF
ON
ON
Table 2. Switch settings for thermocouple type selection
SM815 - MV
4-8 mV
8-16mV
12-24mV
16-32mV
20-40mV
24-48mV
28-56mV
32-64mV
SM815 - V1
0.04-0.08V
0.08-0.16V
0.12-0.24V
0.16-0.32V
0.20-0.40V
0.24-0.48V
0.28-0.56V
0.32-0.64V
SM815 - V2
0.4-0.8V
0.8-1.6V
1.2-2.4V
1.6-3.2V
2-4V
2.4-4.8V
2.8-5.6V
3.2-6.4V
SM815 - V3
4-8V
8-16V
12-24V
16-32V
20-40V
24-48V
28-56V
32-64V
Table 3. Input spans for voltage input models
NOTES
1. All input ranges start at 0 millivolts (or 0°C) with an offset adjustment of approximately ±25% of the millivolt span, using the zero
potentiometer.
2. Table 1 lists maximum and minimum spans for each switch setting. For example with switches 4, 5 & 6 in the on position, the input range can
be set from 0 to 4 mV up to 0 to 8 mV using the span pototentiometer.
Содержание SM815
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