Dwyer Series 682 Industrial Pressure Transmitter, 17-4 PH

Series 682 industrial pressure transmitter for liquids and gases

The Dwyer Series 682 is a rugged pressure transmitter with a capacitive sensor and electronics in a welded stainless steel housing. It outputs 4-20 mA, has non-interactive external zero and span adjustments, and is stated to withstand shock of 200 g and vibration of 20 g from 50 to 2000 Hz. Accuracy including non-linearity, hysteresis and non-repeatability is ±0.13 % of full scale.

Seven Star LLC supplies the Series 682 in Oman and the GCC as an independent supplier in Muscat. The sections below set out the range structure and the points that matter when specifying the unit.

Series 682 range codes

The ordering code is the series 682 followed by a range digit: -0 for 0 to 25 psi (100 psi overpressure), -1 for 0 to 50 psi (150 psi), -2 for 0 to 100 psi (300 psi), -3 for 0 to 250 psi (500 psi), -4 for 0 to 500 psi (1000 psi), -5 for 0 to 1000 psi (2000 psi), -6 for 0 to 3000 psi (4500 psi), -7 for 0 to 5000 psi (7500 psi) and -8 for 0 to 10,000 psi (12,500 psi). A NIST traceable calibration certificate is available as an accessory.

Technical specifications of the Series 682

How the Series 682 reacts to its environment

A capacitive sensing element converts the pressure into an electrical signal, and the electronics sit in a welded stainless housing that meets NEMA 4 (IP65). There are no threaded covers or seals that can loosen, which is why the datasheet suggests off-road equipment, compressor control, refrigeration, hydraulic systems and industrial engines as typical uses.

The 5 ms response time suits pressure that pulsates, for instance in hydraulic circuits, and it also means that pump pulsation will be seen in the signal; add damping in the controller if needed. The zero and span adjustments are accessible from the outside and do not interact, so field trimming of ±0.5 mA is quick.

Compensated temperature range of -20 to 80 °C is narrower than the operating limit of -40 to 125 °C; at extreme temperatures the thermal error is larger.

Series 682 compared with the Series 673 and 3200G

The Series 682 offers higher accuracy and a wider range selection than the economical Series 673 and a fixed cable output, but it is not an explosion-proof or HART unit. Where HART or hazardous-area approval is needed, the Series 3200G is the maker option.

The cable-outlet design makes it suitable for mobile and OEM machinery as well as for plant pipework where a conduit is not required.

Selection and ordering checklist for the Series 682

• Range digit and the highest peak pressure that can occur including pulsation
• Compatibility of 17-4 PH stainless steel with the process fluid
• Process temperature within -40 to 125 °C
• Cable length and sealing of the cable outlet
• Power supply 9-30 V DC
• Calibration certificate

Installing the Series 682

Thread the 1/4 in NPT connection into a pipe tee or manifold using a suitable thread sealant, avoid overtightening on the housing and use the hex area. Protect the 2 ft cable from mechanical damage and terminate it in a junction box.

For hydraulic circuits fit a snubber if pressure spikes may exceed the overpressure limit of the chosen range.

Typical applications in Oman and the GCC

The Series 682 suits compressors, chillers, hydraulic power units, engines and off-road equipment, as well as general industrial pressure monitoring where a hard-wired cable is acceptable. In Gulf installations the NEMA 4 housing resists sand-laden air and washdown.

The nine ranges give a clear selection logic: pick the range whose full scale is comfortably above normal operation but below the stated overpressure. For example, a steady 200 psi process with occasional spikes to 400 psi fits the 0 to 500 psi unit (1000 psi overpressure) better than the 0 to 250 psi unit, whose 500 psi overpressure rating leaves little margin. The accuracy figure is a percentage of full scale, so an oversized range wastes resolution.

Series 682 ranges and overpressure ratings

From the ordering chart.

Information to send with an RFQ for the Series 682

Please send the following.

• Pressure range
• Fluid and temperature
• Cable length if different
• Quantity and delivery date

Site conditions in Oman for the Series 682

Field instruments in Oman are exposed to strong sun, high ambient temperature, wind-blown dust and, on coastal plants, salt in the air. When you specify the Series 682, check the ambient and process temperature limits, the enclosure rating and the wetted and housing materials against the actual installation point, and consider sunshades for transmitters mounted in direct sunlight. Cable entries should be sealed with suitable glands so that dust and moisture cannot enter the housing.

Calibration and verification planning matters as much as selection. Record the range, configuration and tag data of each Series 682 at commissioning, define a check interval that suits the criticality of the loop, and keep the certificates with the plant documentation so that audits and shutdown work can proceed without delay.

Documents and quotation

The manufacturer datasheet for the Series 682 is attached on this page, so the electrical data, terminal assignment and ambient limits quoted above can be checked against the original document before an order is placed.

Seven Star LLC supplies Dwyer products in Oman and the GCC as an independent supplier in Muscat. Send the quantity, the signal types and the project delivery date, and we will confirm availability and lead time in a written quotation.