Detailed Wiring Guide for Dwyer Magnesense® MSX-W10-PA Differential Pressure Transmitter

Detailed Wiring Guide for Dwyer Magnesense® MSX-W10-PA Differential Pressure Transmitter

Proper wiring of the MSX-W10-PA model is critical to ensuring accurate signal transmission to the Building Management System (BMS) and protecting the device from potential electronic circuit damage. Below is a comprehensive guide based on official Dwyer technical specifications.

1. Preparation Before Wiring

• Remove the LCD Display: If your unit is equipped with an LCD, you must remove it before wiring. Pull the LCD directly away from the pins on the circuit board. Only reinstall the display after all wiring is completed.

• Cable Selection: It is highly recommended to use shielded twisted-pair cable. Ground the shield only at the power supply end to prevent ground loop interference.

• Electrical Entry: The device features a 1/2" NPS threaded entry. Ensure the cable gland is tightened properly to maintain the NEMA 4X (IP66) weather-proof rating.

2. 2-Wire 4-20 mA Current Output Wiring

This is the most common configuration for the MSX-W10-PA when transmitting signals over long distances without worrying about voltage drops.

(Figure 1: Current Loop Wiring Diagram)

• Power Requirement: 10-36 VDC.

• Wiring Steps:

  • Connect the Positive (+) lead of the DC power supply to the VDC terminal.

  • Connect the COM terminal of the transmitter to the Positive (+) terminal of the current receiver (PLC/BMS).

  • Connect the Negative (-) terminal of the receiver back to the Negative (-) lead of the power supply to complete the loop.

3. 3-Wire 0-5V / 0-10V Voltage Output Wiring

This mode allows for a selectable voltage output based on the position of DIP Switch 4 (OFF for 0-10V, ON for 0-5V).

(Figure 2: DC/AC Voltage Wiring Diagram)

• Power Requirement: 17-36 VDC or isolated 21.6-33 VAC.

• Wiring Steps:

  • VDC/VAC Terminal: Connect to the power source (Positive for DC or Hot for AC).

  • COM Terminal: Connect to the power supply negative and the negative terminal of the voltage receiver.

  • VOUT Terminal: Connect to the positive terminal of the voltage receiver to transmit the signal.

4. Simultaneous Current and Voltage Output Wiring

The MSX-W10-PA is capable of providing both signal types at once—useful for sending 4-20 mA to a controller while using 0-10V for a local display or auxiliary equipment.

(Figure 3: Simultaneous Output Wiring Diagram)

• Critical Note: This mode DOES NOT support AC power. You must use a 10-36 VDC power supply.

• Wiring Steps:

  • Use the VDC terminal as the common power input.

  • The voltage output and the power supply must have separate wire leads that are only joined at the transmitter's terminal to prevent voltage errors.

  • The COM terminal acts as the common ground for both signal loops.

5. Safety Rules and Technical Guardrails

DLK TRADING SERVICE CO., LTD – Authorized Importer and Distributor of Dwyer instruments – provides the following technical advice:

• Maximum Voltage: Never exceed 36 VDC. Over-voltage will cause permanent circuit failure and void the warranty.

• Load Resistance: For voltage outputs, the receiver must have a minimum impedance of $1000 \Omega$. For current outputs, the maximum loop resistance ($R_{MAX}$) is calculated as follows:

  $$R_{MAX} = \frac{V_{ps} - 10.0}{20\text{ mA DC}}$$

• Polarity Protection: If the transmitter is wired in reverse, it will not function but is protected from damage. If the LCD does not light up, check your terminal polarity.

Once wiring is complete, please refer to our guide on DIP Switch configuration and Calibration to optimize the accuracy of your system.

Related Products:

• Dwyer MSX-W12-PA Pressure Transmitter for Ducts

• Dwyer MSX-W13-PA Differential Pressure Solution