Allen-Bradley 700-FSK3CU23-EX 700-FS One-Shot Timing Relay

Allen-Bradley 700-FSK3CU23-EX 700-FS Timing Relay

Configured for precision pulse-controlled timing execution in automated control loops, the Allen-Bradley 700-FSK3CU23-EX (700-FSK3CU23 One-Shot Timing Relay) provides direct physical/electrical execution. Operating across flexible input limits of 24-240 VAC (50/60 Hz) and 24-48 VDC, this specialized timing unit initiates an adjustable 0.5 to 10 s single-shot duration upon receiving an incoming control trigger. Internal SPDT changeover contacts deliver precise circuit isolation and sequencing capability, while its EX rating permits installation in hazardous industrial areas.

Suffix Breakdown & Model Matrix

The catalog number structure for the Allen-Bradley 700-FS series defines functional features, timing ranges, coil control voltages, and special environmental certifications:

• 700-FS: Base series designation for industrial high-performance IEC timing relays.
• K: Functional mode code indicating One-Shot / Watchdog (pulse-controlled) timing action.
• 3: Time scale range code specifying adjustable timing from 0.5 to 10 s.
• C: Contact output configuration specifying 1 Changeover Contact (SPDT).
• U23: Wide-range control supply rating covering 24-240 VAC (50/60 Hz) and 24-48 VDC.
• EX: Hazardous location protection certification code for ATEX/IECEx hazardous areas.

Hardware Specifications

Allen-Bradley Industrial Control & Bus Architecture

Allen-Bradley control components within the 700-FS product line offer fast backplane bus communication velocity Licences and seamless connectivity across EtherNet/IP deterministic networks. High I/O density scaling allows dense mounting arrangements inside remote terminal cabinets without generating signal cross-talk or inductive feedback. Furthermore, firmware flash compatibility across Rockwell Automation platforms ensures that internal relay status monitoring interacts directly with CompactLogix and ControlLogix PLC racks without signal degradation.

Frequently Asked Questions

Q: How does a pulse-controlled One-Shot function differ from a standard On-Delay timing sequence?

A: A One-Shot relay closes its output contact immediately upon receiving a control pulse and holds it closed for the preset duration (0.5 to 10 s) regardless of input signal persistence. An On-Delay relay waits for the timer to elapse before closing its contacts.

Q: Can the 700-FSK3CU23-EX be installed in high-vibration machinery control panels?

A: Yes. The hardware is tested and rated to IEC 60068-2-6 standards for vibration resistance up to 4 g over 10-500 Hz, preventing contact chatter and accidental relay tripping under heavy mechanical oscillation.

Q: What is the recommended functional alternative if this specific EX model is unavailable?

A: The functional replacement specified by Rockwell Automation is model 700-FSK6UU23-EX, which offers equivalent one-shot logic and control voltage ranges, though wiring terminal positions and physical depth dimensions may vary slightly.

Field Installation Guidelines

Mount the relay vertically onto a standard 35 mm DIN rail inside a rated panel enclosure. Ensure the rail latching mechanism fully locks into place to prevent movement during vibration exposure. Leave at least 10 mm of lateral spacing between adjacent heat-generating components to maintain proper convective cooling across the module housing.

Strip control wiring to 6 mm and secure conductor leads into screw terminals using a calibrated torque screwdriver set to 0.5 to 0.8 Nm. Route AC supply conductors and low-voltage DC trigger lines through separate cable conduits to eliminate electromagnetic noise coupling. Connect the external shielding of control lines to a single-point low-impedance earth ground stud within the main cabinet enclosure before applying power.