Dwyer 645 - Manual

Series 645 Wet/Wet Differential Pressure Transmitter
BULLETIN A-30-65
Specifications - Installation and Operating Instructions
GENERAL
The Series 645 Wet/Wet Differential Pressure Transmitter
is designed for use with any gas or liquid compatible
with 17-4 PH stainless steel, 300 Series stainless steel,
Viton and Silicone O-rings and bleed screw seals. Units
can accurately measure the differential pressure even
when liquid is applied to both ports. The transmitter
contains a fast response capacitance sensor and a
unique isolation system.
The isolation system transmits the motion of the differ-
ential pressure sensing diaphragm from the high line
pressure environment to the dry enclosure where it
moves one of a pair of capacitance plates proportional-
ly to the diaphragm movement. The variable capaci-
tance is converted to a current proportional to the differ-
ential pressure by the capacitance sensing and signal
conditioning circuit located in the enclosure. The elec-
tronic circuit linearizes output versus pressure, stan-
dardizes the output, and compensates thermal effects of
the sensor.
INSTALLATION
The Series 645 Differential Pressure Transmitter is sup-
plied with a mounting bracket and two 6-32
ϫ 3/8 hex
head screws. First attach the bracket to mounting loca-
tion using holes or band clamp notches available on
large section of the bracket. Attach the transmitter to the
bracket by using the two 6-32
ϫ 3/8 hex head screws
and the two tapped holes located on the underside of
the transmitter. See Figure 1 at right.
DWYER INSTRUMENTS, INC.
P. O. BOX 373 MICHIGAN CITY, INDIANA 46361, U.S.A.
Telephone 219/879-8000
Fax 219/872-9057
SPECIFICATIONS
Service: Compatible gases or liquids applied to both pres-
sure and reference ports.
Output: 4 to 20 mA, two-wire.
Supply Voltage: 11 to 30 VDC.
Loop Resistance: 0 to 1000
Ω.
Maximum Line Pressure: 250 psig.
Maximum Overload Pressure: (High side) 1 to 5 psi: 20
ϫ
FS, 10 to 25 psi: 10 ϫ FS, 50 psi: 5 ϫ FS, 100 psi: 2.5 ϫ FS;
(Low side) 2-3
ϫ FS.
Zero and Span: Adjustable, non-interactive, ±1 mA.
Accuracy: ±0.25% FS.
Temperature Limits: Operating: 0 to 175°F (-22 to 80°C),
Storage: -65 to 260°F (-54 to 126°C).
Response Time: 30 to 50 msec.
Thermal Effects: (includes zero and span) ±0.02% FS/°F, 30
to 150°F (-1 to 65°C).
Wetted Parts: 17-4 PH stainless steel, 300 Series stainless
steel, Viton and Silicone O-rings and bleed screw seals.
Housing: Stainless steel/Aluminum.
Process Connection: 1/4 - 18 NPT(F).
Electrical Connection: Barrier strip terminal block with con-
duit enclosure and .875 (22 mm) diameter conduit opening.
Weight: 14.4 oz (0.4 kg).
R1-124069-00
2.960 2.150
2.440
1.750
2.840
1/4-18 NPT
HIGH PRESSURE PORT
BLEED
SCREWS
1/4-18 NPT
LOW PRESSURE PORT
Ø.875 CONDUIT OPENING
.940
Mounting