Troubleshooting - ACR Electronics SmartReader Plus Reference Manual

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The EH-020A is applicable for measurements between -20 and 40°C (-4 and 104°F) and 10 to

90% RH.

The accurate measurement of temperature and humidity depends primarily on the information

supplied by a particular sensor. SmartReader Plus 2 data loggers use temperature and

humidity sensors with rugged qualities designed for minimal or no maintenance (under normal

operating conditions).

The SmartReader Plus 2's on-board thermistor is chemically stable and not significantly

affected by aging. It will typically drift less than 0.1°C over a period of several years. The

relative humidity sensor, although subject to accuracy degradation when exposed to

contaminants and/or extreme environmental conditions, will drift typically less than 1% per

year (under clean conditions). You should check your RH sensor periodically and, if

necessary, recalibrate or replace it.

1.4.4

Troubleshooting

If you are getting what appear to be wrong readings, consider the following before recalibrating

the sensors. Sensors sample the atmosphere (or medium) in the immediate vicinity of the

sensors themselves. The physical state of the atmosphere and its degree of uniformity and

turbulence will limit the validity of a measurement at some distance from the sensor. This

becomes especially apparent for the measurement of ambient temperature and relative

humidity.

In a room, temperature and RH levels may vary dramatically from location to location. Such

factors as air stratification, drafts and proximity to heat or humidity sources (people,

equipment, moisture, solar gain, etc.) can contribute to a wide variance in conditions even

within a small confined area. The individual sensors associated with your SmartReader Plus 2

measure and record temperature and RH only in one location. They do not, in any way,

represent an overall reading.

If you decide to check the calibration of your SmartReader Plus 2 RH sensor using a Sling

Psychrometer, keep in mind the following:

· Any instrument that requires a person to be present at, or in very close proximity to the

RH sensor in order to get a reading, will have a measurement error introduced to it.

SmartReader Plus Data Logger

Figure 2-2: EH-020A Connection

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