MSA SUPREMA Touch, Инструкция по установке и обслуживанию, Страница: 85 / 309

SUPREMATouch 84
Maintenance and Service
MSA
US
Calibration by Means of the Sensor
Make sure before the calibration that the sensors have recovered. This procedure can also be
used to compensate for small deviations in the output current of the sensors from the system set-
up of the SUPREMATouch [4 mA = 0 % of the measuring range, 20 mA = 100 % of the measuring
range]. The deviations in the current should not exceed ± 0.5 mA, however, or otherwise the error
evaluation [leaving the measuring range in one direction or the other] will be impaired.
NOTE: At least 2 people are required to perform the calibration. To avoid communication prob-
lems between Person 1 operating the SUPREMATouch and Person 2 supplying the sensors with
gas, we recommend the usage of a set of appropriate two-way radios.
Again, the required zero and test gases, test adapters, and hose connections [see operating and
maintenance instructions of the sensor] for supplying the gases are a necessary precondition for
a successful calibration.
The duration and flow rate of the zero and test gas supplies can be found in the operating and
maintenance instructions for the sensor in question.
For the calibration, person 1 [at the SUPREMATouch] and person 2 [at the sensor in question]
must perform the following steps:
Person 1:
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Select the “Maintain/Calibration” menu.
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Select the input to be calibrated in the “Measure Point” field.
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Enter 0 % of the measuring range in the field “Zero Gas” as the zero gas concentration.
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Enter the test gas concentration in the field “Test Gas”.
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If the test gas is not the same as the reference gas entered in the “Setup/Measure Points”
menu, select the test gas being used in the field “Test Gas Type”.
NOTE:
Sensors with a linear output signal:
The test gas concentration should be in the upper third of the measuring range. The displayed
signal voltage is calculated according to the formula:
Signal = C / 100 * 1600 mV + 400 mV.
Sensors with a nonlinear output signal must be calibrated to the rating. [Take note of the LEL.]
Signal voltage for full scale: 2,000 mV ± 10 mV.
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Start calibration with the “Start” button.