Scaime IPM25 - Millivolt Per Volt Calibration Procedure

IPM25 User Manual
21
Millivolt per Volt Calibration Procedure
This procedure outlines how a millivolt per volt calibration might be undertaken.
1. Ensure that the factory settings for gain and offset are set to 1 and 0, respectively. See millivolt per volt
calibration section to do this.
2. Begin by connecting up the model IPM25 and a high precision Multimeter to the calibration source set at
2.5mV/V with a 350 load.
3. Take readings at 2.5mV/V and 0mV/V on both the model IPM25 and the high precision Multimeter.
4. Record your excitation reading.
5. To convert Multimeter reading to a millivolt per volt reading, divide the output reading on the meter by the
measured value of excitation.
6. The gain is then calculated by dividing the difference in the span of the Multimeter readings by The model
IPM25 reading.
7. This value can then be entered into the millivolt per Volt Calibration menu under 5.0 gAIn then press
to
confirm.
8. The offset of the model IPM25 is derived by subtracting the 0mV/V Multimeter reading from the model IPM25
reading.
9. Again, enter this under 5.0 OFFS in the millivolt per Volt Calibration menu then press to confirm.
Setup Diagram
Worked Example
IPM25 handheld (mV/V) Multimeter (mV/V)
0 mV/V 0.000338 0.000204423
2.5mV/V 2.47993 2.499846
1. Gain =  Multimeter reading /  IPM25 reading = (2.49984 - 0.000204423) = 1.008008mV/V (6dp)
(2.47993 - 0.000338)
2. Offset = Multimeter reading – IPM25 reading = 0.000204423 - 0.000338 = - 0.000096mV/V (6dp)
Output Voltage (mV)
millivolts per volt (mV/V)= _____________
Excitation (V)
Calibration Source
2.5mV/V @ 350 Ω
ld
IPM25 Reading e.g.
0.000338mV/V @ 0mV/V
2.47993mV/V @ 2.5mV/V
Multimeter Reading e.g.
12.234mV @ 2.5mV/V
000.001mV @ 0mV/V
Excitation – 4.8939 V @ 2.5mV/V
Excitation – 4.8918 V @ 0mV/V
Using formula above [1]:
0.000204423mV/V @ 0mV/V
2.499846mV/V @ 2.5mV/V
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