Instruction and operating guideline CO-detector
Type:
VCD2 CO-Detector
6
Calibration Guidelines
CiTiceL transmitters are supplied precalibrated, and
the sensitivity of the device should not drift by more
than 2% of full signal per month. The circuit board
has a single push button which can be used to
calibrate the transmitter should this be required.
The standard mounting system allows easy aspiration
using the calibration plug provided. With the plug in
place and sealing caps fitted, the CiTiceL is
completely isolated from the atmosphere. With sealing caps removed, calibration
gas can be supplied through one inlet and exhausted through the other.
Calibrating to Cross Sensitive Gases
Electrochemical CiTiceLs are cross sensitive to certain non-target gases.
Information regarding cross sensitivities for particular sensors can be found on
the product datasheets. It is important to remember however, that cross
sensitivity data is only very approximate and cross sensitivities will vary between
sensors and sensor batches. Therefore, it is not advisable to calibrate sensors or
transmitters to non-target gas as this will result in a degree of measurement
error.
Recommended Gas Flow Rates
A minimum flow rate is required to ensure accurate calibration - it also means
that the response from a CiTiceL is equivalent in configurations where gas is
flowing over the sensor and those where the sample is allowed to diffuse into the
sensor. The minimum flow rate which is required will be different depending on
the CiTiceL type – these are shown in the table below.
These flow rates are based on gas delivery apparatus used at City Technology
Ltd. Other designs of gas delivery may have an influence on the flow rates
required. EasyCal Circuit Board Layout
Standard User Calibration Method (Span Gas = 20 mA Signal)
