05701-A-0325 | Honeywell | DC Input Card

Configured for power distribution management in System 57 sub-rack enclosures, the Honeywell 05701-A-0325 (05701-A-0325) DC Input Card provides direct physical power entry and routing for rack-mounted electronics. The module accepts a nominal 24 V DC supply, distributing power via the sub-rack backplane while incorporating integrated fuse protection, RFI filtering, and reverse polarity protection for the connected control instrumentation.

Hardware Specifications

Channel-to-Channel Isolation

The 05701-A-0325 utilizes internal diode-based isolation to separate the primary power supply unit (PSU) and auxiliary (AUX) standby battery inputs. This isolation architecture ensures that a voltage drop or fault in the primary supply does not back-feed into the battery backup circuit. Furthermore, the module provides RFI filtering to suppress electromagnetic noise, maintaining a clean power rail for the sensitive instrumentation across the backplane. This power conditioning is necessary to preserve the signal integrity of the control modules and prevent transient-induced errors during power state transitions.

Frequently Asked Questions

Q: Can this card be hot-swapped while the sub-rack backplane is under load?

A: No. The card must be removed or inserted only when the rack is de-energized to prevent arcing at the terminal block (TB1) or backplane connector, which could lead to power surges.

Q: How is backplane current managed when multiple catalytic cards are present?

A: In configurations exceeding eight 5704 Catalytic Cards, current load should be distributed by powering Control Cards through their associated Quad Relay Interface Cards, while using the 05701-A-0325 solely for Engineering Card power.

Field Installation Guidelines

• Terminal Block Usage: The card features a two-part terminal block (TB1). Utilize this modular design to disconnect field wiring as a block, minimizing the need to remove individual wires during maintenance.
• Stand-by Battery Connection: Auxiliary connections are provided for backup battery supplies. Ensure that the backup voltage polarity matches the primary supply to prevent diode conduction issues.
• Fuse Inspection: The card incorporates an onboard fuse for overcurrent protection. Verify fuse continuity during power-up or following a rack-wide power loss.
• Wiring Separation: Ensure that DC supply cables are routed separately from signal lines to prevent induced electromagnetic interference on the instrumentation bus.