Siemens SIPROCESS GA700 Quick Start Manual page 102

Commissioning: Sequence
8.7 [1.5] Calibration
Types of calibration
You can set the following types of calibration:
Table 8- 1 Types of calibration ("Customer calibrations")
Calibration
1-point zero gas calibration
1-point span gas calibration
2-point calibration
1-point calibration with substitute gas
to shift the characteristic offset
Scope/reference
Single calibration
Calibrations can be run as single or total calibrations. Only the selected measuring range is
calibrated in a single calibration, while the calibration parameters of all other measuring
ranges are not affected.
Total calibration
In a total calibration, at first the selected measuring range is calibrated as with single
calibration. But the newly calculated calibration parameters of this leading measuring range
are converted for all other measuring ranges. This means all measuring ranges can be
calibrated with the same calibration parameters.
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Description
This calibration eliminates drifts in the zero point. The setpoint corresponds to the
actual value in the zero point.
This calibration eliminates drifts in the span point by adjusting a sensitivity factor
accordingly. The setpoint corresponds to the actual value in the span point.
In this type of calibration, zero gas validation and span gas calibration take place
successively.
Because the thermal conductivity sensor of the CALOMAT 7 shows a stable char-
acteristics gradient after an operating time of about 3 months, regular 2-point cali-
bration is no longer necessary. A monthly 1-point offset calibration is sufficient in
this case; it essentially corresponds to a 1-point zero gas calibration. Keep in mind
during the calibration that the measurement effect of the span gas used must be
within the characteristic of the gas pair. Nitrogen can be used as substitute gas in
most cases. The calibration setpoint must be determined in advance by introduc-
ing the intended substitute gas and writing down the associated measured value
as future setpoint.
This type of calibration always has the character of a zero point calibration (offset
shift of the characteristic).
We recommend a 2-point calibration after running a 1-point calibration with substi-
tute gas twice. This is, however, done at the discretion of the device operator.
Compact Operating Instructions, 06/2017, A5E31805656-05
Quick Start