Specifications

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14
Measured Variables
Relative humidity
Indication range 0...100 %RH
Resolution 0.1 %RH
Typical temperature dependence ±0.2 %RH
over the entire operating temperature range
Temperature
Indication range -40
0
+180
0
F (-40
0
+180
0
C)
(temperature measurement range depends on the probe used)
Resolution 0.1
0
F (0.1
0
C)
Typical temperature dependence 0.007° F (0.004
0
C)
of electronics
Typical additional error caused
by the HMI 38 at 68°F (+20
0
C) 0.11°F (±0.06
0
C)
One and two-point calibration through front panel keypad.
Calculated Variables
Typical ranges (depend on the probe used)
dewpoint temperature -40...+212 °F (-40...+100 °C)
mixing ratio 0...500 g
H20
/kg d.a.
absolute humidity 0...600 g
H20
/m
3
wet bulb temperature 32...+212 °F (0...+100 °C)
Data Logging
Storage capacity
in automatic logging 254 measurements from each probe
in catch logging 127 measurements from each probe
Logging interval from 10 s to 99 h
or catch logging
Measurement speed
one probe approx. 1 s
two probes approx. 2 s
Analog Outputs
Two analog outputs 0...1 V & 0...5 V
freely selectable and adjustable
Typical accuracy of analog ±0.05% FS
output at +68°F (+20°C)
Typical temperature dependence 0.003% (0.005 %/°C FS)
of analog output
Serial Interface
Data interfaces RS 232C, RS 485
(asynchronous, only one available at a time)
Data I/O speed (one chosen) 300, 600, 1200, 2400,
4800, 9600
Communication parameters
data bits 7 or 8
stop bits 1 or 2
parity even, odd or none
mode full or half duplex
Connector D-type female D9S
Data format display/printer or computer
compatible ASCII characters
General
Display 2 x 6 character alphanumeric
high contrast, wide-view angle
LCD
Character height 3.85 mm (0.15")
Keyboard 4 x 4 tactile membrane switches
Number of probes 1...2
Supply voltage 12 VDC (11...16 V), 0.2 A
Rechargeable battery pack 8 NiCd 1.2 V cells,
standard 'AA' size
operating time in continuous use 8 hours
operating time in data logging 24 hours
charging time 6 hours
Power consumption during charge 3 W maximum
Recommended external load >2 kohm (to ground)
for 0...1V output
Recommended external load >10 kohm (to ground)
for 0...5 V output
Housing material ABS plastic
Operating temperature range 32...122 °F (0...+50 °C)
Storage temperature range -4...+158 °F (-20...+70 °C)
Operating humidity range 95 %RH maximum,
noncondensing
Storage humidity range 90 %RH maximum
Note: The HMI 38 can be operated at a higher relative
humidity than stored, because the air in a warm instrument
has a lower relative humidity than ambient air.
Specifications subject to change without notice.
Dimensions in mm (inches)
294.3 (11.58)
200 (7.87) 90 (3.54)
80 (3.14)
TECHNICAL DATA - HMI 38 Humidity Data Processor
HMI 38
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