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DewPro MMY31
1.2 Introduction
Unit descrip-
The DewPro MMY 31 is a loop powered dew point transmitter for the trace moisture
tion
range. The transmitter includes an aluminum oxide planar sensor element, a stainless
steel probe, a weather proof enclosure, and microprocessor electronics. It is designed to
be installed "in-line". Various mounting hardware such as flange and compression fittings,
are available for mounting into a process chamber, process pipe, etc. The DewPro
MMY31 measures dew point temperature in
Fig. 2
1.3 Theory of Operation
4 to 20 mA
The DewPro MMY 31 microprocessor controlled electronics operate with a voltage supply
Loop
of 12 to 32 V DC. At the nominal 24 V DC supply, the maximum loop resistance is 750
Ohm. The signal is represented by the 4 to 20 mA loop current and is directly proportional
to the dew point temperature range of -90
Planar Sensor The heart of the MMY31 is the newest Planar sensor element. It incorporates a new,
superior aluminum oxide sensor that provides longer calibration stability, improved
corrosion resistance, and faster speed of response. The sensor, mounted on a ceramic
substrate, also has a reduced temperature coefficient.
Calibration
Each DewPro is factory calibrated against precise NIST certified moisture references and
has an accuracy of +/- 2
once a year, depending on application and the required accuracy. GE General Eastern
has multiple calibration facilities world wide providing trace ability to national and
international standards.
GE General Eastern
Installation and Operation Manual
o
C or
116
86
MODEL:
MMR 31
SERIAL NO :
SUPPLY:
9...32 VDC
D EWPO INT RANG E:
P max:
PSIG
Thread
G ½
12,7
o
C to +10
o
C dew point. Recalibration should be performed approximately
o
F.
50,8 mm
(2,0")
74,6 mm
(3,0")
Compression fitting
o
o
o
C (-130
F to +50
F).
5
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