Description
Honeywell 05701-A-0325
Technical Specifications
- Input Type: Dry contact or 24 VDC wet sensing input
- Channel Quantity: 8 isolated DC input channels
- Sensing Voltage: 24 VDC loop supply from card internal circuit
- Input Isolation: Channel group isolation, 1000 VAC isolation grade
- Backplane Bus: System 57 proprietary rack bus
- Operating Temperature: -10 °C to +55 °C
- Power Consumption: 3 W maximum
- Form Factor: Eurocard plug-in rack card
Functional Features Each input channel has independent overvoltage and reverse polarity protection. Input wetting current is limited to prevent damage to dry contact field devices. Open circuit and short circuit diagnostic function detects wiring failure on field input loops. Front panel LED array shows individual channel active state and module fault status. Sampled input status data is transmitted to main controller with checksum protection. Input filter time constant suppresses transient electrical noise and contact bounce.
Application Scenarios Gas detection cabinet door interlock and access status monitoring Emergency shutdown system auxiliary contact feedback acquisition Ventilation fan running status discrete signal collection Fire system cross contact input for gas panel interlock logic System 57 gas rack spare I/O replacement
Performance Parameters
- Input sampling refresh interval: 100 ms
- Input filter delay: Configurable 10 ms to 500 ms
- Input impedance: 10 kΩ nominal
- Diagnostic coverage: 100 % for open and short field wiring faults
- Insulation resistance: >1000 MΩ at 500 VDC
Material Composition FR4 multilayer PCB, optocoupler isolation chips, current limiting metal film resistors, TVS surge suppression diodes, X7R ceramic filter capacitors, screw terminal wiring block, flame retardant plastic front panel, gold plated backplane edge connector.
Structural Features Standard eurocard form factor matching System 57 rack slot. Detachable front screw terminal block for field DC input wiring. Front panel LED indicators grouped for power, module fault and each channel status. Internal isolation barrier separates field DC circuit and rack logic bus circuit. Anti-keying notch on card edge prevents reversed installation.
Working Principle Internal 24 VDC sensing supply is applied to each input channel loop. Field contact closure pulls input circuit to active state, while open contact creates inactive state. Optocoupler transfers status signal across isolation boundary to local logic chip. Logic chip filters transient bounce and packages channel status into bus frame. Frame is sent to main gas controller for interlock logic execution. If loop resistance falls outside calibrated window, wiring fault flag is generated.
Installation Requirements Field input wiring uses twisted pair cable and runs separate from gas sensor analog signal cables. Dry contact field devices must not carry external voltage source on input loop. Mount card only inside original System 57 metal rack enclosure. Verify input polarity marking when wiring wet voltage signals. Set filter parameter in system configuration to match contact mechanical bounce characteristic.
Usage Notes External voltage source must not be injected into input terminals. Do not connect AC voltage signals to this DC input card. Card diagnostic fault requires field wiring inspection before fault reset. Do not modify internal current limiting resistor network.
