General Eastern Dew-10 Operating Manual

DEW-10 DEW POINT TRANSMITTER GUIDE

For Information in th is ma n ual is believed to be rel i-
able. However, GE Infrastructure Sensing makes no warranty,

expressed or implied, as t o its accuracy and assumes
no liability arising out of its use by others. We reserve
the right to change this manual without prior notice,

1-24-1992
PART NO. A40096273/B.00 ECO NO.2114
Copyright  1999 GE Infrastructure Sensing

TABLE OF CONTENTS

INTRODUCTION TO DEW-10 DEW POINT TRANSMITTER .................................................4

PERFORMANCE AND OPERATING RANGES .........................................................................4

TO SPECIFY POWER/SIGNAL/CONFIGURATION OF DEW-10 TRANSMITTER................5

INSTALLATION OF DEW-10 - XX0: WALL MOUNT.............................................................. 6

Installation Hint ..................................................................................................................6

INSTALLATION OF DEW-10 - XX1: DUCT MOUNT.............................................................. 7

Installation Hints..................................................................................................................7

INSTALLATION OF DEW-10 - XX2: PIPE MOUNT.................................................................8

Installation Hints..................................................................................................................8

WIRING GUIDE FOR THE DEW-10............................................................................................9

Power Connections..............................................................................................................9

Signal connections for DEW POINT ..................................................................................9

Signal connections for AIR TEMPERATURE (on wall mount only) ..............................10

Conversion of Internal Transmitter to Loop Power...........................................................10

Connection of Internal Transmitters to PCB No. ..............................................................10

Listing of Terminal and Connector Designations..............................................................11

REQUIREMENT FOR PERIODIC MAINTENANCE................................................................13

DESCRIPTION OF DEW-10 TRANSMITTER SUBASSEMBLIES..........................................14

PCB No. 1 Subassembly....................................................................................................14

PCB No.2 Subassembly.....................................................................................................14

Sensor Subassembly ..........................................................................................................14

PERIODIC MAINTENANCE PROCEDURES............................................................................15

PROCEDURE FOR MIRROR SURFACE CONDITION CHECK.............................................15

PROCEDURE FOR MIRROR SURFACE CLEANING..............................................................16

PROCEDURE FOR FINE OPTICAL BALANCE ADJUSTMENT............................................16

COARSE BIAS ADJUSTMENT PROCEDURE .........................................................................17

TABLE OF CONTENTS

(continued)

DIAGNOSTIC PROCEDURES FOR DEW-10 TRANSMITTER SUBASSEMBLIES..............18

Diagnostics for PCB No. 1.............................................................................................................18

Diagnostics for PCB No. 2.............................................................................................................18

Diagnostics for Sensor...................................................................................................................18

Diagnostics for Internal Transmitter ........................................................................................... ...18

Quick Calibration Check................................................................................................................19

Trouble Shooting Guide.................................................................................................................19

IDENTIFICATION OF SUBASSEMBLIES AND PARTS.........................................................20

Common parts to DEW-10 Transmitter.........................................................................................20

INSTRUMENT PRODUCTS WARRANTY POLICY ................................................................21

PRODUCT RETURN PROCEDURE...........................................................................................22

INTRODUCTION TO DEW-10 DEW POINT TRANSMII1ER

The DEW-10 Series is a family of low-cost, high-performance chilled mirror dew point
transmitters. In the sensor a metal mirror surface is controlled at the dew point - the temperature
at which water vapor condenses from the surrounding air. The temperature of the mirror is
continuously measured by a platinum resistance thermometer (PRT). The measurement is
available directly as resistance or may be internally converted to an analog signal. For the wall
configuration only, an air temperature probe may be integrated into the unit.

The measurements of dew point and air temperature are stable, accurate and traceable to
National standards. As long as the Transmitter is in good working order, outputs are accurate to
+/- 0.5 degrees Celsius. The calibration of each PRT is confirmed by GE Infrastructure Sensing
Instruments against transfer standards calibrated by the National Institute of Standards and
Technology (formerly NBS). Each transmitter comes with the full support that GE Infrastructure
Sensing offers for all its products.

PERFORMANCE AND OPERATING RANGES

Mirror depression: 40 C (72 F) at 25 C (77 F) ambient

(See Operating Range Diagram)

Accuracy: +/- 0.5 C (+/- 1.0 F)

Repeatability: +/- 0.05 C (+/- 0.1 F)

Response Time: 2 minutes max for one time constant at 100 meters/300 feet per

minute

Environmental Limits
Min/Max Sensor: -lOCto70C(OF to 160F)
Min/Max Electronics: 0 C to 60 C (32 F to 120 F)
Flow Rate: 100 to 1000 meters (300 to 3000 feet) per minute for duct/pipe
Max. Pressure: 0 to 300 mbar (0 to 5 psig)

Power Requirements
Standard Power: 24 +/- 6 VDC at 350 mA
Optional Power: 24/115/230 VAC +/- 10% 50/60 Hz 10 VA

Available Output Signal
Standard output: DIN 43760 4-wire PRT (100 Ohms @ 0 C)
Optional output: Linear 4-20mA/1-5VDC loop/source powered

Dimensions
Shipping Weight: 10 pounds
Dry Weight: 6 pounds
Shipping Dimensions: 14” x 6” x 20”

TO SPECIlY POWER/SIGNAL/CONFIGURATION OF DEW-10

DEW-

10

P

S

C

TRANSMITTER

(0) 24 VDC (A) 4 wire PRT
(0) Wall Mount
Standard Standard

(1) 24 VAC (B) 4 –20
(1) Duct Mount
0-100 F

(2) 115 VAC (C) 4-20 mA
(2) Pipe Mount

(3) 230 VAC (D) 4-20 mA

-40-140 F

-40-60 C

(X) 4-020 mA
User Selected

Identify your Dew-10 specifications:

DEW-10 –

POWER SIGNAL
CONFIGURATION

OWER

IGNAL

ONFIGURATION

INSTALLATION OF THE DEW-10 - XX0: WALL MOUNT

(

1) Identify installation point. Unit is mounted with chassis against wall and metal cap or
optional air temperature probe toward floor. Avoid detectable down drafts and allow easy
access for periodic maintenance.

(2) Remove plastic cover and use holes in chassis as template for locating mounting screws.

The plastic cover is attached to chassis by velcro strips. To remove cover, pull away from
chassis.

(3) Wire according to guide that follows installation instructions. Unit will power up

immediately upon connection to power.

(4) Check operation by moving switch SW1 on PCB No. 1 to CHECK position. LED should

light within two minutes to confirm that unit can operate correctly. If LED does not light
see trouble shooting guide. If LED does light return SW1 to OPERATE position. LED
will go out as dew condenses on the metal mirror in the sensor.

(5) Replace plastic cover.

Installation Hint

As air is sampled by convection currents through the sensor cavity, the transmitter is sensitive to
down drafts and orientation. If down drafts cannot be eliminated a baffle may be mounted above
the transmitter to deflect the air flow around unit