Lake Shore 234, Руководство пользователя

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Lake Shore Model 234/234D User’s Manual
Service 5-5
5.4 CALIBRATION
The section covers Required Test Equipment in Paragraph 5.4.1, Reference
Calibration procedure is provided in Paragraph 5.4.2. Finally, the calibration
procedure is provided in Paragraph 5.4.3. See Figure 5-3 for the Model 234
PCB layout. Allow 5 minutes warm-up before performing any calibration
procedures. The following resistance ranges are implemented on the Model
234 Temperature Transmitter:
Approximate Internal Internal
Sensor Reference Sensor A/D Voltage
Scale Resistance Resistance Voltage Reading
0 1 – 6
Ω
10
Ω
5 mV 0.15 to 1.0 V
1 4.5 – 12.5
Ω
100
Ω
5 mV 0.8 to 2.2 V
2 9 – 60
Ω
100
Ω
10 mV 0.35 to 2.2 V
3 45 – 125
Ω
1 k
Ω
5 mV 0.8 to 2.2 V
4 90 – 360
Ω
1 k
Ω
10 mV 0.55 to 2.2 V
5 290 – 1.25 k
Ω
3.16 k
Ω
10 mV 0.55 to 2.2 V
6 900 – 3.6 k
Ω
10 k
Ω
10 mV 0.55 to 2.2 V
7 2.9 k – 12.5 k
Ω
31.6 k
Ω
10 mV 0.55 to 2.2 V
8 9 k – 36 k
Ω
100 k
Ω
10 mV 0.55 to 2.2 V
9 29 k – 300 k
Ω
316 k
Ω
10 mV 0.21 to 2.2 V
Scale changing depends on the forward A/D voltage reading. The lower and
upper range in resistance is approximately subject to variations in gains and
offsets.
Note the sensor voltage continually switches between positive and negative
values to obtain the forward and reverse readings. Thus, the sensor and A/D
voltage cannot be read reliably with a DC voltmeter.
Calibration results in a forward A/D reading of approximately 0.65 or 2 volts
at the time of calibration (See table below). This allows for over-ranging
dependent on variation in gains and offsets. The reference resistance and
approximate A/D voltages used for each value of calibration resistance is
shown below.
Internal
Calibration Reference Approximate
Resistance Resistance A/D Voltage
1
Ω
10
Ω
1.0 V
10
Ω
100
Ω
2.0 V
100
Ω
1 k
Ω
2.0 V
1 k
Ω
3.16 k
Ω
0.65 V
1 k
Ω
10 k
Ω
2.0 V
10 k
Ω
31.6 k
Ω
0.65 V
10 k
Ω
100 k
Ω
2.0 V
100 k
Ω
316 k
Ω
0.65 V