Yokogawa PW702 S1 DC Power Supply

Configured for stable power distribution in industrial control architectures, the Yokogawa PW702 S1 (PW702) Power Supply Module provides direct physical/electrical execution of AC-to-DC conversion, voltage regulation, and field-side circuit protection.

Hardware Specifications

Yokogawa DCS Process Control Characteristics

• 4-20 mA HART loop protocol: The 48 VDC output provides the necessary loop power for HART-enabled field transmitters. This output voltage is mandatory to sustain the required signal loop resistance and modem communication bandwidth in long-distance process control applications.
• FOUNDATION Fieldbus / Profibus PA connectivity: The PW702 stabilizes the DC bus required for fieldbus power conditioners. This connectivity is mandatory to ensure that digital fieldbus segments operate within their specified voltage tolerances, preventing communication timeouts caused by bus under-voltage.
• Channel-to-channel isolation: The power supply incorporates galvanic isolation between the AC input stage and the 48 VDC output. This isolation is mandatory to protect sensitive DCS input/output modules from mains-borne transients and high-voltage surges that could damage internal logic components.
• Cold junction compensation (CJC): The PW702 maintains thermal stability for precision measurement circuits. This is mandatory for temperature measurement applications where the power supply shares a common ground with analog input modules, ensuring that noise injection does not influence the reference accuracy of the CJC.

Frequently Asked Questions

Q: Can the PW702 S1 be operated in parallel with another unit for current redundancy?

A: Parallel operation is not supported unless specified by the system integration manual and performed using an external redundant power module (diode ORing). Direct parallel connection can lead to instability and uneven load sharing, potentially triggering the short-circuit protection circuits.

Q: How does the unit protect against load-side faults?

A: The PW702 features integrated overload and short-circuit protection. If the 10 A current limit is exceeded, the module enters a hiccup or latching shutdown mode. Resetting the supply is mandatory to restore operation once the field-side fault is cleared.

Field Installation Guidelines

• Mounting: Install the PW702 in a vertical orientation within the cabinet to facilitate natural convection cooling. Maintaining the specified clearances around the unit is mandatory to ensure the internal thermal management system functions within the 0 to 55 deg C range.
• Grounding: Bond the power supply chassis to the cabinet’s main safety earth bus using a low-impedance cable. This is mandatory to ensure the internal surge protection components effectively shunt transient voltages to ground, protecting both the supply and the load.
• Wiring: Use the removable terminal block for all connections. Ensure that the input AC and output DC wires are adequately sized for the 10 A current rating. Separation of at least 150 mm from low-voltage signal cabling is mandatory to prevent inductive coupling and radiated EMI from impacting nearby DCS inputs.