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2.2. Technical Specifications and Special Instructions for Oxygen detectors
2.2.1. Transfer curves for OLCT 20 / OLCT 40 detectors
The following curve shows the transmitter output current value as a function of gas
concentration. Where the user connects the transmitter to a device other than a device manufactured
by ISC/OLDHAM, he must check that the transfer curve is fully compatible with its input
characteristics to ensure that the information generated by the transmitter is correctly interpreted.
Equally, the device must supply a suitable power supply voltage, allowing for cable voltage losses.
2.2.2. Metrological details
Maximum concentration 30% O
2
Type and number CT5020 CELL
Principle 2-electrode electrochemical
(Measurement of oxygen
concentration by volume)
Estimated service life 30 months
Storage 4°C < T < 12°C
10% < RH < 60%
Temperature range -20°C to +45°C
Humidity range 20% RH to 95% RH
Pressure range 1 bar ± 10%
Accuracy at 20°C 15 to 21% O
2
± 0.5% vol O
2
1 to 14% O
2
± 0.6% vol O
2
Repeatability < 2% of signal
T90 response time < 15 seconds
Effect of temperature (0 to 40°C) < 0.5% vol O
2
Effect of humidity (10% to 90% RH)
The measurement is lower as a
result of the air being diluted by
water vapour
Sensitivity drift over time < 2% per month
Zero stabilisation time following
power-up
30 to 60 minutes
0 %
30.0 % 36.0%
20.0 mA
4.0 mA
1 mA
% O2 concentration
by volume
Output Current in mA
Fault
23.2 mA