Honeywell 05701-A-0325 DC Input Cards

The Honeywell 05701-A-0325, also cataloged as the 05701-A-0325 DC Input Card, operates as a dedicated hardware component for routing external DC power to the sub-rack backplane within Honeywell System 57 platforms.

Hardware Specifications

Process Control Integration & Power Distribution

• Sub-Rack Power Routing: The primary DC power supply enters the rack through the card's pluggable terminal block TB1. The power paths route directly through the Engineering Card to the sub-rack backplane, supplying operating power to all installed control and monitoring cards.
• Dual-Source Diode Isolation: The main power supply unit (PSU) and the auxiliary (AUX) standby battery inputs are electrically isolated from one another via high-current onboard diodes. This configuration prevents reverse-feeding of current back into a faulted supply line.
• Backplane Current Management: To mitigate the risks of excessive backplane currents in installations featuring more than eight 5704 Catalytic Cards, the system architecture allows control cards to be powered externally through their associated Quad Relay Interface Cards. This limits the backplane DC Input Card's duty cycle strictly to powering the Engineering Card.

Frequently Asked Questions

Q: Can the 05701-A-0325 be replaced without disconnecting individual field wires?

A: Yes. The card features a two-part pluggable terminal block, TB1. Technicians can unplug the entire pre-wired connector assembly from the card header, allowing rapid module replacement without rewiring errors.

Q: What type of overcurrent protection is featured on the card?

A: The card is fitted with an accessible onboard fuse that protects the sub-rack backplane and connected modules from downstream short circuits or overcurrent faults originating from the main 24 VDC power supply.

Field Installation Guidelines

• Terminal Torque Boundaries: Secure the primary and auxiliary 24 VDC lines into the two-part TB1 connector using a precision screwdriver. Tighten to the manufacturer's recommended torque rating to ensure a low-resistance electrical interface.
• Stand-by Battery Integration: When connecting an auxiliary standby battery to the AUX terminals, verify that the battery voltage matches the nominal 24 VDC parameters of the primary power supply.
• Module Slot Alignment: Slide the DC Input Card into the designated card guides on the sub-rack. Ensure the rear edge connector mates flush with the backplane sockets before securing the front retaining clips.
• Chassis Shield Grounding: Verify the rack chassis frame is properly connected to the system earth grounding bus bar to enable optimal execution of the integrated RFI filtering networks.