Dwyer 626 Precision Pressure Transmitter

Series 626 Industrial Pressure Transmitters

The SERIES 626 AND 628 Pressure Transmitters monitors the pressure of compatible gases and liquids with 0.25% FS accuracy for 626 models or 1.0% FS accuracy for 628 models. The design employs a pressure sensor that can convert a single positive pressure into a standard 4 to 20 mA output or field selectable voltage output. The terminal block, as well as a zero adjustment button, are easily accessed under the top cover. The Series 626 and 628 are designed to meet NEMA 4X (IP66) construction.

Specification

INSTALLATION

1. Location: Select a location where the temperature of the unit will be between 0 and 175°F (-18 to 79°C). Distance from the receiver is limited only by total loop resistance. The tubing feeding pressure to the instrument can be practically any length required, but long lengths will increase response time slightly.

2. Position: The transmitter is not position sensitive. However, all standard models are originally calibrated with the unit in a position with the pressure connection downward. Although they can be used at other angles, for best accuracy, it is recommended that units be installed in the position calibrated at the factory.

3. Pressure Connection: Use a small amount of plumber’s tape or other suitable sealants to prevent leaks. Be sure the pressure passage inside the port is not blocked.

4. Electrical Connections Wire Length — The maximum length of wire connecting the transmitter and receiver is a function of wire size and receiver resistance. Wiring should not contribute to more than 10% of the receiver resistance to total loop resistance. For extremely long runs (over 1000 ft or 305 m), choose receivers with higher resistance to minimize the size and cost of connecting leads. Where wiring length is under 100 feet (30.5 m), wire as small as 22 AWG can be used. CURRENT (4 to 20 mA) OUTPUT OPERATION An external power supply delivering 10 to 35 VDC with minimum current capability of 40 mA DC (per transmitter) is required to power the control loop. See Figure 1 for connection of the power supply, transmitter, and receiver. The range of appropriate receiver load resistance (RL) for the DC power supply voltage available is expressed by the formula:

RL Max = Vps – 10 /20 mA DC

Shielded cable is recommended for control loop wiring. Electrical connections to the Series 626/628-CB pressure transmitters are made to the terminal block located inside the housing. Remove the screws and lift off the cover. Lift off the terminal block for wiring. Wire as show in Figure 1 or 2. Use Figure 1 for current output connection. Use Figure 2 for current output with optional LCD display. If ordering pre-wired cable, black wire is negative (-) and red wire is positive (+)

VOLTAGE (0 to 5, 1 to 5, 0 to 10, or 2 to 10 V) OUTPUT OPERATION To select the voltage output that is going to be used, configure the DIP switches according to the Figure 4 below. Power must be cycled whenever dip switches are changed to select output.

MAINTENANCE/REPAIR Upon final installation of the Series 626/628-CB Industrial Pressure Transmitter, no routine maintenance is required. The Series 626/628-CB is not field serviceable and is not possible to repair the unit. Field repair should not be attempted and may void warranty.

WARRANTY/RETURN Refer to “Terms and Conditions of Sale” in our catalog and on our website. Contact customer service to receive a Return Goods Authorization number before shipping the product back for repair. Be sure to include a brief description of the problem plus any additional application notes

FAQ