ZMOD4450 Datasheet

© 2019 Integrated Device Technology, Inc.

10

October 30, 2019

8.2 Environmental Temperature and Humidity

The sensor module is tested, qualified, and functional in the operation range of 0°C to +25°C. Figure 3 shows the module’s response during

operation to variations in relative humidity with and without ethylene stimulation.

Figure 3. Humidity Influence at 4°C for Ethylene Stimulation

8.3 Accuracy and Conditioning

All IDT gas sensor modules come with electrical and chemical factory calibration with data stored in the module’s nonvolatile memory (NVM).

Using the software provided by IDT and the calibration coefficients in the NVM will lead to stable measurements. The ZMOD4450 will respond

to typical refrigeration gases immediate upon start-up; however, a conditioning period of 48 hours in a refrigeration environment is recommended

to improve stability and get maximum performance, as the module algorithm is able to learn about the refrigeration environment over time.

Users who require an absolute measurement with the maximum achievable accuracy are advised to re-calibrate the sensor with a known

organic compound. This enables an absolute accuracy of ±15%; see Table 7. For some environments, an interference response to siloxanes

is of concern; however, IDT’s ZMOD4450 gas sensors have been proven to be resistant against siloxanes. A maximum potential life-time

exposure has been simulated in all ZMOD4450 operation modes by applying the chemicals D4 (octamethylcyclotetrasiloxane) and D5

(decamethylcyclopentasiloxane) in high concentration for several hundred hours.

Table 7.

Typical ZMOD4450 Sensor Module Accuracy Achievable with Calibration

Symbol

Parameter

Conditions

Minimum

Typical

Maximum

Unit

Accuracy

With additional calibration

±15

%

Durability to Siloxanes

Change in sensitivity

±5

%

1E+5

1E+6

1E+7

50

60

70

80

90

100

Relative Humidity [%]

Clean Air

Ethylene 0.2 ppm