Dwyer Series 605 Magnehelic® Differential Pressure Indicating Transmitter

Product Overview

The Dwyer Series 605 Magnehelic® Differential Pressure Indicating Transmitter offers simultaneous local indication on an analog scale and conversion of pressure into a standard two-wire, 4-20 mA signal. It is designed for measuring positive, negative, or differential air and compatible gases, with accuracies as low as ±.5% of full scale. The mechanical design is based on the proven Magnehelic® differential pressure gage.

Specifications

Gage Specifications

• Service: Air and non-combustible, compatible gases.
• Wetted Materials: Consult factory.
• Accuracy: See chart.
• Stability: ±1% FS/yr.
• Pressure Limits: See chart.
• Temperature Limits: 20 to 120°F (-6.67 to 48.9°C).
• Process Connections: 1/8" female NPT.
• Size: 4" (101.6 mm) dial face, 5" (127 mm) O.D. x 2-11/16" (68.3 mm) for -SS Bezel; 4-3/4" (120.7 mm) O.D. x 2-21/32" (67.5mm) Bezel.
• Weight: 1 lb, 12.6 oz (811 g).
• Agency Approvals: CE.

Transmitter Specifications

• Accuracy: See chart (includes linearity, hysteresis, repeatability).
• Temperature Limits: 20 to 120°F (-6.67 to 48.9°C).
• Compensated Temperature Range: 32 to 120°F (0 to 48.9°C).
• Thermal Effect: ±0.025% FS/°F (0.045% FS/°C).
• Power Requirements: 10-35 VDC (2-wire).
• Output Signal: 4-20 mA.
• Zero and Span Adjustments: Protected potentiometers.
• Loop Resistance: DC; 0-1250 Ω maximum.
• Current Consumption: DC; 38 mA maximum.
• Electrical Connections: Screw terminal block.
• Mounting Orientation: Diaphragm in vertical position. Consult factory for other position orientations.

Model Chart

Installation

1. Location: Select a location where the temperature is between 20°F and 120°F. Tubing length is not critical but long lengths may increase response time. Avoid surfaces with excessive vibration.
2. Position: For maximum accuracy, the diaphragm should be vertical. Specify if mounting in other than a vertical position is required.
3. Pressure Connections: Two 1/8" female NPT ports are available. Plug the unused set. Connect the positive pressure source to the "HI" port and the negative (Vacuum) source to the "LOW" port. The opposite port must be vented to atmosphere. Use an A-331 Filter Vent Plug for dusty environments.

4. Mounting: The Series 605 Transmitter can be panel mounted or surface mounted.
   • A. Panel Mounting: Cut a 4-3/4" (120 mm) diameter hole in the panel. Insert the unit from the front, slip on the mounting ring, install the split snap ring in the bezel groove, seat the mounting ring against the snap ring, and thread the four screws through the tapped holes into the rear of the panel.
   • B. Surface Mounting: Drill three 3/16" diameter holes for mounting screws and cut a 7/8" x 1-1/8" hole for terminal strip access as shown in the hole location drawing. Insert screws from the rear of the panel and thread into the transmitter case. If rear pressure connections are used, make 1/2" diameter holes as shown.
   • C. For -SS Bezel Installation: Provide a 4-9/16" opening in the panel. Insert the gage and secure with supplied mounting hardware.
5. Zeroing: Ensure the pointer aligns with zero on the scale when no pressure is applied and both ports are vented to atmosphere. Adjust the pointer using the small slotted screw at the center-bottom of the gage face. Do not use the SPAN and ZERO knobs for this adjustment.

Electrical Connections

CAUTION: Do not exceed specified supply voltage ratings. Permanent damage not covered by warranty will result. This unit is not designed for AC voltage operation.

Electrical connections are made to the two-screw terminal strip on the rear of the case. Polarity is indicated by + and - signs. A schematic diagram is provided (Figure B).

An external power supply delivering 10.0-35 VDC with a minimum current capability of 40 milliamps is required. Refer to Figure B for connection of the power supply, transmitter, and receiver. The appropriate receiver load resistances (RL) for the power supply voltage are shown in Figure C. Shielded two-wire cable is recommended for control loop wiring. The negative side of the loop may be grounded. The receiver can be connected in either the positive or negative side of the loop. Reversing polarity will prevent loop operation but will not damage the transmitter.

The maximum length of connecting wire is a function of wire size and receiver resistance. The resistance of the connecting wires should not exceed 10% of the receiver resistance. For runs over 1,000 feet, use receivers with higher resistances. For runs up to 100 feet, No. 22 Ga. wire can be used.

The Series 605 transmitters can also be used with receivers requiring 1-5 V input. To do this, insert a 250 Ω, 1/2 watt resistor in series with the current loop and in parallel with the receiver input. Connect points X and Y to the receiver input, with X as positive and Y as negative or ground. The resistor should be connected at the panel end of the transmitter current loop, close to the receiver input.

Output Ranging

Each Series 605 transmitter is factory calibrated to produce 4 mA at zero scale reading and 20 mA at full scale reading. If the pressure versus output signal relationship needs to be checked or adjusted, follow these procedures:

1. Connect an accurate milliammeter (approximately 30 mA full scale) in series with the current loop.
2. Vent both pressure ports to atmosphere. If necessary, adjust the pointer zero screw to align the pointer with zero on the scale. Connect a pressure source to the high pressure port, plug the other high pressure port, and vent the low pressure port(s) to atmosphere. The instrument must be ranged in the position it will be used.
3. Apply electrical power and slowly increase pressure, observing the loop current. It should increase above the 4 mA zero reading.
4. Use the supplied spanner type key to adjust the SPAN knob. Apply pressure until the pointer aligns with the full scale reading, then adjust the SPAN knob for a 20 mA reading.
5. Relieve all pressure and allow a few seconds for settling. Adjust the ZERO knob for a 4 mA current loop reading.
6. The SPAN and ZERO controls are interactive. Repeat steps 4 and 5 until consistent 4 mA and 20 mA readings are obtained.
7. Remove the milliammeter and proceed with final installation.

Multiple Units with Common Power Supply

Several Series 605 transmitters can be operated with a single power supply (Figure D). Ensure the supply has sufficient capacity. The minimum current requirement is calculated by multiplying the number of units by 20 mA.

Maintenance

No routine maintenance is required after final installation. Periodic calibration checks are recommended. The Series 605 Differential Pressure Transmitter is not field repairable. If repair is needed, return the unit freight prepaid to the factory. Include a description of the problem and any relevant application notes. Contact customer service to receive a return goods authorization (RGA) number before shipping.

Recycling Information: This symbol indicates that waste electrical products should not be disposed of with household waste. Please recycle where facilities exist. Check with your Local Authority or retailer for recycling advice.