647-3 Pressure Transmitter
Contents
1.2. 8 891 4963 www dwyer inst com e mail info dwyer inst com ELECTRICAL CONNECTIONS Make all wiring connections with the power off All cir cuits must be wired to the National Electrical Code Class 1 and in conformance with all applicable codes and requirements with approved wiring practices See Figure 1 below for appropriate wiring connections Wiring Connections 24 VDC Power 4 20 mA 2 wire Field Conversion 4 20mA 2 wire Loop Signal to 1 5 VDC Signal 24 VDC In 1 24 VDC In 2 4 20 mA Signal Out Ea 3 250 Ohms Common No Connection Figure 1 OPERATION After applying power allow approximately 20 to 30 min utes for stabilization of signal When operating at low differential pressures of less than 5 w c or in applications where the pressure is fluctuat ing rapidly it is advisable to insert snubbers for air flow restrictors in the input lines This serves to steady the output signal and keeps the signal from bouncing erratically Adjustments The Series 647 transmitters are adjusted for the speci fied range at the factory and should not require further adjustments If necessary or desireable the zero and span may be adjusted however the requested full scale range as shipped is established with fixed resistors min imizing the range of adjustment The average full scale adjustment is 10 of the range shipped Copyright 1997 Dwyer Instruments Inc Z Zero Con
3. BULLETIN A 30 647 Dower e STRUMENTS a on GENERAL The Series 647 Wet Wet Differential Pressure Transmitter is designed for use with compatible liquids or gases and can accurately measure differential pressure down to 1 H20 The transmitter contains a fast response piezore sistive sensor and a unique isolation system ideal for HVAC systems filter monitoring variable speed drive control air liquid flow monitoring and process control The Series 647 Wet Wet Differential Pressure Transmitter features excellent repeatability low hysteresis and accurate operation over a broad temperature range Units have an adjustable zero and span and feature reverse polarity protection MECHANICAL INSTALLATION NOTE The Series 647 Wet Wet Differential Pressure Transmitter can be mounted in any position however be alert to moisture passing through a non waterproof elec trical connector The unit can measure gauge vacuum or differential pressure Follow the directions below for the appropriate port connections Gauge Positive pressure sensing Connect media pres sure to port labeled HIGH with port labeled LOW vented to atmosphere Vacuum Negative pressure sensing Connect media pressure to port labeled LOW with port labeled HIGH vented to atmosphere Differential pressure sensing Connect the higher of the two media pressures to port labeled HIGH and the lower of the two
4. pressures to port labeled LOW DWYER INSTRUMENTS INC P O BOX 373 MICHIGAN CITY INDIANA 46361 U S A MENTS INC 2 15 16 PHYSICAL DATA Service Compatible gases or liquids on both pressure and reference sides Accuracy 1 0 FS Output 4 to 20 mA 2 wire Supply Voltage 18 to 30 VDC Loop Resistance 4002 18 VDC 6002 24 VDC 10002 30 VDC Zero and Span Adjustable 10 Max Line Pressure 60 psig Max Overload Pressure Ranges 1 w c to 5 psi 20 psi 15 psi range 45 psi 30 psi range 60 psi Compensated Temperature Range 32 to 122 F 0 to 50 C Storage Temperature 40 to 212 F 40 to 100 C Thermal Effects Zero 0 05 FS F Span 0 05 rdg F Stability 1 5 FS output year Wetted Parts Brass vinyl glass filled polyester silicon Buna N and fluorosilicon Housing Gasketed steel epoxy painted NEMA 4 Process Connection 1 8 NPT F Electrical Connection Screw terminals reverse polarity pro tected Weight 14 oz 397 g MODELS Model Number Range Model Number O to 1 psid 0 to 5 psid O to 15 psid O to 30 psid The Series 647 Wet Wet Differential Pressure Transmitters have 1 8 NPT female port connections ALWAYS USE A SECOND WRENCH TO HOLD THE PORT HEX NUT THEREBY ELIMINATING THE POSSI BILITY OF ROTATING THE BRASS PORT FITTING Use thread sealant or teflon tape to insure proper sealing Phone 219 879 8000 Fax 219 872 9057 Lit by Fax 88
5. trol is adjusted for 4 mA output signal at O psi or minimum pressure S Span Control is adjusted to change the full scale range of the transmitter Due to resistor values required to compensate for the null off set of the sensing module evidence of Zero and Span interaction may be experienced in readjusting Do not adjust the bridge balance and temperature com pensation controls WARNING Fluid hammer and surges can destroy any pressure transducer and must always be avoided A pressure snubber should be installed to eliminate the damaging hammer effects Fluid hammer occurs when a liquid flow is suddenly stopped as with quick closing solenoid valves Surges occur when flow is suddenly begun as when a pump is turned on at full power or a valve is opened quickly MAINTENANCE After final installation of the Series 647 Wet Wet Differential Pressure Transmitter no routine maintenance is required Periodic checks of connections is recom mended Please contact Dwyer Instruments Inc before returning unit for repair to review information relative to your application When returning a product to the facto ry carefully package and ship freight prepaid Be sure to include a complete description of the application and problem and identify any hazardous material used with the product Printed in U S A 11 97 DWYER INSTRUMENTS INC P O Box 373 Michigan City Indiana 46360 U S A Phone 219 879 8000 Fax 219 872 9057
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