Veris Industries HS SERIES Data Sheet

Humidity Monitoring | Replaceable Humidity Element

HS SERIES

Easy Field Replacement for Veris Deluxe
Humidity Sensors

HS

U.S. Patent No. 5,844,138

The HS replaceable humidity element is designed to lower costs and
reduce downtime. It features thin-film capacitive technology for
superior accuracy and exceptional resistance to contaminants. It is
compatible with all Veris deluxe sensors, making replacement quick and
easy. No need to install a new humidity sensing device, just insert a new
element into the unit and resume operation.

These humidity elements are calibrated in a high accuracy, NIST
traceable, humidity generator. Each sensor is digitally calibrated at four
different relative humidity levels over an eight-hour period. Calibration
data is programmed into the replaceable sensing element. This
computer-controlled digital calibration eliminates errors associated with
manual “trimming.” A certificate of calibration is provided with NIST
versions of the HS.

Veris’ calibration system produces known humidity values using the
fundamental principle of the “two pressure” generator developed by
NIST (H-4622). The two-pressure method involves saturating air with
water vapor at a given pressure and temperature. Saturated gas then
flows through an expansion valve where it is isothermally reduced to
chamber pressure. Gas temperature is held constant during pressure
reduction, so relative humidity at chamber pressure is calculated as the
ratio of two absolute pressures.

Temperature uniformity in the chamber is maintained by circulating a
temperature controlled fluid through a shell surrounding the test space.
Highly accurate pressure measurements are made using NIST traceable
piezoresistive transducers. The resulting system accuracy is better than

0.5% RH over all ranges and temperatures.

This system is capable of continuously supplying accurate humidity
values for instrument calibration, evaluation, and verification.

ORDERING INFORMATION

Accuracy

HS

1 = 1%*
2 = 2%
3 = 3%
5 = 5%

Example:

HS

Note: 1-year limited warranty.

NIST

N = NIST
(1% & 2% models only)
X = None
(2%, 3%, & 5%
models only)

5 X X

X

*1% HS sensors us ed in outdoor app lications are limi ted
by the devi ce to 2% accuracy.

TM

HQ0001794.F 0117

HS Digital Humidity Sensor

Serial Number:

This digital sensor has been computer profiled and calibrated at multiple relative humidity levels using standards traceable to
the National Institute of Standards and Technology through test #H-4622.

The humidity standard produces an atmosphere of known humidity based on the "two-pressure" principal which is to saturate
an air stream with water vapor at a given pressure and temperature. The saturated air stream is then reduced to test pressure.
The humidity at test pressure is then the ratio of the two absolute pressures, corrected for vapor pressure and enhancement
factor ratios.

Date: Accepted by:

Certificate of Performance

HOURS

2

4

6

0%

-3%

10% 30% 50% 70% 90%

-2%

-1%

0%

+1%

+2%

+3%

10%

20%

30%

40%

50%

60%

70%

80%

90%

100%

Sample interval: 3 minutes

Reference

12.0%

20.0%

30.0%

40.0%

50.0%

60.0%

70.0%

80.0%

90.0%

Reading

12.53%

20.44%

29.94%

40.12%

49.80%

59.98%

69.84%

79.43%

88.80%

Difference

+0.53%

+0.44%

+0.06%

+0.12%

+0.20%

-0.02%

-0.16%

-0.57%

-1.20%

Humidity Monitoring | HS Series

HQ0001794.F 0117

TM