Dwyer 677B User Manual

Bulletin P-677B

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OVER

Series 677B Differential Pressure Transmitter

Specifications - Installation and Operating Instructions

eries 677B Differential Pressure Transmitters are designed to measure

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pressures as low as 0.1 in w.c. with ±0.4% accuracy. Use Series 677B for building
energy management systems, environmental pollution control, oven
pressurization, lab and fume hood control, HVAC and VAV applications. The
transmitter features 15 psid overpressure, reverse polarity protection and

MI/RFI protection. Internal regulation permits use with unregulated DC power

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upplies. The NEMA 4 housing allows for versatile mounting locations and

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ntegral mounting tabs simplify installation.

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Mounting

Series 677B is designed for mounting by using the two (2) slots (suitable for #6
and #8 screws) that are provided on the mounting baseplate. For optimum
performance, isolate the instrument from vibration and provide relatively clean, dry
air to the pressure ports.
Note: Even though there is no flow through the 677B, a filter is located in both the
high and low pressure ports for use in extreme dust or moisture conditions.

In most applications, preferred installation is with the baseplate mounted vertically
and located on a flat surface in a junction box or attached to a nearby beam. Quick
and easy field replacement is possible by removing the two case screws that hold
the housing to the baseplate and lifting the housing free. The baseplate will remain
mounted and can be used with the replacement units housing.

NOTICE

Piping

Two (2) 3/16˝ OD barbed pressure fittings are provided for pressure connection
with 3/16˝ or 1/8˝ ID push on tubing. For best results, 1/8˝ ID tubing is suggested
for tubing lengths up to 100 feet long.

The overpressure limit with the new tension diaphragm construction is up to 15 psi
regardless of range.

The axis most sensitive to vibration is the one perpendicular to
the baseplate. Avoid mounting with maximum vibration along
axis.

SPECIFICATIONS

ervice: Air and non-conductive, non-corrosive gases.

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etted Materials: 302 SS, glass, nickel, silicone rubber and brass.

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ccuracy: ±0.4% FS* at room temperature.

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*RSS includes non-linearity, hysteresis and non-repeatability.

Stability: ±1% FS/yr.
Temperature Limits:

Operating and Compensated: 0 to 185°F (-18 to 85°C);

torage: -65 to 220°F (-54 to 105°C).

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Pressure Limit: 15 psi (100 kPa).
Thermal Effects: (Includes zero and span) <0.028% FS/°F, 0 to 185°F (-18 to

85°C).

Power Requirement: 16 to 32 VDC.
Output: 4 to 20 mA DC, 2-wire.
Zero and Span Adjustments: Internally accessible potentiometers,

noninteractive.

Response Time: Approximately 10 ms.
Max. Loop Resistance: DC: 0 to 800 Ω.
Process Connection: 3/16˝ OD barbed brass pressure fitting.
Enclosure Rating: NEMA 4 (IP65).
Weight: 11.5 oz (330 g).
Agency Approval: CE.

Model
677B-01
677B-02
677B-03
677B-04
677B-05
677B-06
677B-07
677B-08
677B-11
677B-12
677B-13
677B-14
677B-15

Range (in w.c.)

0 to 0.1
0 to 0.25
0 to 0.5
0 to 1
0 to 2.5
0 to 5
0 to 10
0 to 25
0 to ±0.05
0 to ±0.1
0 to ±0.25
0 to ±0.5
0 to ±1

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: [phone] e-mail: [e-mail]

Phone: [phone] www.dwyer-inst.com

Electrical

P

OWER

SUPPLY

16-32 VDC

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RESSURE

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RANSMITTER

RECEIVER

The Series 677B is a two (2) wire circuit (+SUPPLY, -RECEIVER) with a 4 to 20 mA
output. The unit is calibrated at the factory using a 250 ohm load at 24 VDC.

IRING DIAGRAM FOR 677B SERIES

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alibration

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The 677B series is factory calibrated and should require no field adjustment.
However, the zero adjustment is provided near the screw terminal strip. Whenever
possible, any zero and/or span offsets should be corrected by software adjustment in

he user’s control system. Use the zero and span adjustments on the 677B series only

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f absolutely necessary. The 677B series is calibrated in the vertical position at the

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actory (baseplate vertical). For use in any other orientation, position the unit and

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follow the adjustment procedure listed below. If a change in range is needed, contact
the Customer Service Department for a replacement in the appropriate range.

Zero Adjustment

hile monitoring the current output with both pressure ports open to atmosphere, the

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ero may be adjusted. For unidirectional pressure changes, turn the zero adjustment

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crew until a reading of 4 mA (± .16 mA) is achieved. For bidirectional ranges, set the

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zero to 12 mA (± .16 mA).

MAINTENANCE

Upon final installation of the Series 677B Transmitter, no routine maintenance is

equired. The Series 677B is not field serviceable and should be returned if repair is

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eeded (field repair should not be attempted and may void warranty). Be sure to

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nclude a brief description of the problem plus any relevant application notes. Contact

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customer service to receive a return goods authorization number before shipping.

©Copyright 2014 Dwyer Instruments, Inc. Printed in U.S.A. 5/14 FR# R8-443887-00 Rev. 3

DWYER INSTRUMENTS, INC.

P.O. BOX 373 • MICHIGAN CITY, INDIANA 46360, U.S.A. Fax: [phone] e-mail: [e-mail]

Phone: [phone] www.dwyer-inst.com