Series 638 Pressure Transmitters has superior long term stability and repeatability with ±0.5% accuracy. Stainless steel NEMA 4X enclosure. Output is 4-20 mA with 10-30 VDC power supply.
Series
638 Pressure Transmitter Ranges
to 10,000 PSI 0.50%
Full Span Accuracy, 4-20 Ma Signal
Series 638 Pressure
Transmitters
employ a polysilicon sensor for superior longterm stability and
repeatability with ±0.5% accuracy. They are FM approved intrinsically
safe. Stainless steel NEMA 4X enclosure is ideal for corrosive media in
hazardous environments. Output is 4-20 mA with 10-30 VDC power supply.
NIST traceability with calibration certification is standard.
The 638 Series Pressure Transmitter is ideal corrosive media in harsh
environments!
FEATURES:
Service: Liquid, Gas or vapor
Process Connection: 1/8" male NPT
Wetted Material: 17-4 PH SS
Accuracy: ±0.50% FS
Temperature Limits: -20 to 180°F
Pressure Limits: 2X Maximum range
Supply Voltage: 10 to 30 VDC
Output: 4 to 20 ma 2-wire
Zero and Span Adjustment: Adjustable
Enclosure: Stainless Steel and Valox
Conduit Connection: 1/4" - 18 Knockout
Designed to meet NEMA 4X
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The 638 Series Pressure Transmitter |
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Standard 638 Models. |
638 Models - FM Approval |
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A Little Bit About Using Zener Barriers and Galvanic Isolators |
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The MTL5041/5045 Galvanic Isolators provide total intrinsically safe isolation for communication with Dwyer® pressure transmitters approved for location in hazardous areas. Galvanic isolation eliminates the need for a high integrity earth ground required when using shunt diode type safety barriers. DIN rail mounting and plug-in signal and power connectors simplify installation and maintenance. Compatible Models: 637, 638, 639, 608, 2200, 2900
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The MTL7706/7787 is an intrinsically safe (IS) shunt-diode barrier that can be used to communicate with and provide isolations for certain Dwyer® transmitters approved for use in hazardous areas. These barriers limit the amount of energy allowed to pass into the hazardous area, which inhibit ignition in flammable atmospheres. Requires high integrity earth ground Compatible Models: 637, 638, 639, 608, 2200
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What is a Good ground resistance value? |
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There is a good deal of confusion as to what constitutes a good ground and what the ground resistance value needs to be. Ideally a ground should be of zero ohms resistance. There is not one standard ground resistance threshold that is recognized by all agencies. However, the NFPA and IEEE have recommended a ground resistance value of 5.0 ohms or less. The NEC has stated to “Make sure that system impedance to ground is less than 25 ohms specified in NEC 250.56. In facilities with sensitive equipment it should be 5.0 ohms or less.” The goal in ground resistance is to achieve the lowest ground resistance value possible that makes sense economically and physically.
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Please visit Industrial Process and Sensor for more info.