FCT18-CR Series
Bistable Relay
Bistable Relay
with Impulse Control
Industrial-grade impulse latching relay with ultra-wide voltage range, maintaining output state without continuous power — ideal for memory and toggle switching applications.
Wide-voltage 12–240V AC/DC
Bistable / Impulse Latching
No timing adjustment needed
DIN rail mount
18mm slim design
1×SPDT / 2×SPDT
16A @ 250V AC
NPN / PNP
IP40 Front
Bistable Latching
Each impulse on control terminal S toggles the output state. No continuous power needed to maintain relay position.
Memory Function
Retains last state even after supply voltage interruption — resumes previous position on power-up.
Enhanced Anti-EMI Design
Reinforced circuit ensures stable toggling without false triggering in noisy environments.
12–240V
Wide Supply Voltage
AC/DC universal — one relay fits nearly all control systems worldwide.
18mm
Ultra-Slim Housing
Saves precious DIN rail space with compact 18mm width.
1×10⁷
Mechanical Life
Exceptional durability for high-frequency switching applications.
📋 Models & Ordering
| Model | Supply Voltage | Output Contact | Trigger Type | Control Terminal | Datasheet |
|---|---|---|---|---|---|
| FCT18-CR1WN | 12–240V AC/DC | 1 × SPDT | NPN | A2 – S | 📄 Download PDF |
| FCT18-CR1WP | 12–240V AC/DC | 1 × SPDT | PNP | A1 – S | 📄 Download PDF |
| FCT18-CR2WN | 12–240V AC/DC | 2 × SPDT | NPN | A2 – S | 📄 Download PDF |
| FCT18-CR2WP | 12–240V AC/DC | 2 × SPDT | PNP | A1 – S | 📄 Download PDF |
💡 Naming convention: W = Wide voltage (12–240V AC/DC), N = NPN trigger (S to A2), P = PNP trigger (S to A1), 1 = 1×SPDT, 2 = 2×SPDT.
⚙️ Technical Specifications
🔌 Input
| Input Terminal | A1 – A2 |
| Supply Voltage | 12–240V AC/DC |
| Power Consumption | AC 3.5VA / DC 2.0W |
| Voltage Tolerance | -15% ~ +10% |
🎛️ Control Circuit
| Control Terminals | A1–S (PNP) / A2–S (NPN) |
| Control Pulse Length | min. 25ms / max. unlimited |
| Function | Bistable (impulse latching) |
| Switching Action | Each pulse toggles output state |
🔌 Output
| Contact (CR1 series) | 1 × SPDT |
| Contact (CR2 series) | 2 × SPDT |
| Rated Current | 16A @ 250V AC |
| Mechanical Life | 1×10⁷ operations |
| Electrical Life | 1×10⁵ operations |
📐 Physical & Environmental
| Dimensions | 18 × 90 × 64 mm |
| Mounting | DIN rail EN 60715 |
| Protection Degree | IP40 (front) / IP10 (terminals) |
| Operating Temp. | -20°C ~ +55°C |
| Storage Temp. | -30°C ~ +70°C |
📜 Standards & Certifications
| Compliance | GB/T 14048.5, IEC 60947-5-1, EN 6812-1 |
| Contact Configuration | SPDT: 11(COM)-12(NC)-14(NO) 2nd pole: 21(COM)-22(NC)-24(NO) |
| Pollution Degree | 2 |
| Max. Cable Size | AWG 13–20 / 0.4 N·m |
📈 Function Diagram – Bistable Toggle Operation
• The relay operates as an impulse bistable switch: each pulse on the control terminal S toggles the output contact R.
• First pulse: Output R closes (NO contact makes, NC breaks).
• Second pulse: Output R opens (NO breaks, NC makes).
• Third pulse: Output R closes again, and so on.
• The output state is maintained even if the supply voltage is removed — when power returns, the relay stays in the last memorized position.
• Minimum control pulse length: 25 ms. No maximum limit.
🎬 See it in Action
🔧 Wiring & Terminal Layout
Terminal Identification
A1 — L / + (Supply)
A2 — N / - (Supply)
S — Control Signal
11 — COM
12 — NC
14 — NO
21 — COM (2nd pole)
22 — NC (2nd pole)
24 — NO (2nd pole)
⚠️ Safety Note: Keep the power supply disconnected during the entire installation process. Carefully check the wiring diagram and follow it correctly. Adhere to the specified voltage and current limits for each connection terminal.
NPN models (WN): Control signal between S and A2.
PNP models (WP): Control signal between S and A1.
🕹️ How It Works
- Apply Supply Voltage: Connect A1 (L/+) and A2 (N/-) to a 12–240V AC/DC power source. The green LED illuminates.
- Toggle Output via Control Signal: Send a pulse to terminal S (referenced to A1 for PNP, A2 for NPN) with a minimum duration of 25 ms. Each pulse toggles the output state.
- Output State Indication: The red LED indicates the relay position — ON when NO (14/24) is closed, OFF when NC (12/22) is closed.
- Power Loss Behavior: If supply voltage is removed, the relay remembers its last state. On power restoration, the previous position is maintained without an extra control pulse.
🏭 Typical Applications
Lighting Control
Staircase or corridor light toggling with multiple pushbuttons
Staircase or corridor light toggling with multiple pushbuttons
Remote On/Off Switch
Pulse-operated latching for remote equipment control
Pulse-operated latching for remote equipment control
Pump Alternation
Change pump state with a single impulse — no constant signal needed
Change pump state with a single impulse — no constant signal needed
PLC Memory Extension
Keep outputs in desired state after PLC stop or power cycle
Keep outputs in desired state after PLC stop or power cycle
Access Control
Impulse-driven door strikes or gate latches
Impulse-driven door strikes or gate latches
Conveyor Toggle
Start/stop conveyor sections with simple momentary buttons
Start/stop conveyor sections with simple momentary buttons
🔗 Related Products
Explore other time relays in the FCT18 series:
❓ Frequently Asked Questions
🔹 What is a bistable relay, and how does it work?
A bistable relay toggles its output state each time a control pulse is applied to terminal S. It maintains the last state even if the power supply is removed, acting as a memory switch. No continuous control signal is needed.
🔹 Does the FCT18-CR require any time setting?
No. Unlike other FCT18 time relays, the CR series has no adjustable time parameters. It simply toggles with each impulse. The green and red LEDs indicate power and output status.
🔹 What happens after a power failure?
The relay stores its last output position internally. When power is restored, the output returns to the exact same state as before the interruption — no extra pulse is needed.
🔹 What is the minimum pulse width for reliable toggling?
The control signal must stay active for at least 25 milliseconds. Shorter pulses may be ignored. There is no upper limit — you can hold the signal indefinitely.
🔹 Can I use this with both AC and DC supply voltages?
Yes. The FCT18-CR accepts 12–240V AC or DC on terminals A1–A2, making it suitable for almost any control panel worldwide.
🔹 What is the mechanical lifespan of the contacts?
The relay boasts a mechanical life of 1×10⁷ operations, giving outstanding durability for frequent toggling applications. Electrical life is 1×10⁵ operations at rated load.
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