EUCHNER CTS-C1-BP-CC-FLX-AP-USA Guard Locking Safety Switch

Compact guard locking with up to 5000 N holding force

The EUCHNER CTS-C1-BP-CC-FLX-AP-USA (order no. 172870) is a transponder-coded safety switch with guard locking from the CTS series. The housing measures only 135 x 31 x 31 mm, yet the bolt holds a guard closed with a maximum locking force of 5000 N (FZh 3800 N), so it fits narrow door frames and aluminium profile guards where larger interlocks do not. Guard locking works on the closed-circuit current principle: a spring keeps the door locked until the solenoid is energised, so the guard stays shut during a power failure.

This is a FlexFunction device. The switch itself has no fixed coding level or guard-lock monitoring setting; both are decided by which function actuator is taught in. Depending on the actuator, guard-lock monitoring is active or inactive and the actuator code is evaluated at a high or low coding level. One switch type therefore covers personnel protection and process protection tasks.

Technical specifications

Choosing the function actuator

The actuator is not included and must be ordered with the switch. EUCHNER lists four function actuators for the CTS: A-FLX-D-0C-167919 (guard-lock monitoring, high coding level), A-FLX-D-0D-169044 (door position monitoring, high coding level), A-FLX-D-0E-169045 (guard-lock monitoring, low coding level) and A-FLX-D-0F-169046 (door position monitoring, low coding level). On pins 5 and 6, the monitoring outputs change meaning with the actuator: with a guard-lock actuator pin 5 reports guard locking and communication and pin 6 the door position.

Guard-lock monitoring is the setting for protecting people from run-down motion; the door position configuration suits process protection. High coding level means the switch accepts only the actuator taught in. The actuator is carried on a floating bearing, so it tolerates vibration and offset mounting on hinged and sliding doors, including small door radii.

Accessories and installation

Optional parts from EUCHNER include the retrofittable escape release AE-E-D-172426, its extension AY-ERS-50-172441, a padlockable lockout bar AE-L-D-171364 and the mounting plate AM-P-171775 for profile widths of 30, 40 and 50 mm. Two auxiliary releases (front and rear) let a trained person unlock the guard during a fault. The RGB LED diagnostics are visible from three sides. Because the switch is wired in stand-alone mode, evaluate both safety outputs in a safety relay or safe input. Protect inductive loads with a free-wheeling diode.

Documents and quotation

The official EUCHNER product page linked below covers this variant, its functions, ordering data and downloads. For a quotation, state the order number 172870, the function actuator, any escape release or mounting plate, and the quantity. Related interlocks are listed under Safety Switches and Guard Locking.

How the CTS-C1-BP-CC-FLX-AP-USA works in a safety circuit

The CTS-C1-BP-CC-FLX-AP-USA reads the RFID transponder in its actuator without contact. When the actuator is inserted and its code is accepted, the bolt can extend and the guard is locked by spring force. The switch then switches both safety outputs FO1A and FO1B on. These p-switching semiconductor outputs carry test pulses so that a downstream safety relay or safe PLC input can detect cross-circuits and short circuits. When the machine is safe to access, the controller energises the solenoid, the bolt retracts and the outputs switch off before the door can be opened. Because the device works on the closed-circuit current principle, a power failure leaves the guard locked; the front and rear auxiliary releases are provided so trained staff can open the door during set-up or a fault.

EUCHNER rates the device up to category 4 / PL e according to EN ISO 13849-1 and SIL 3 for guard position and guard lock monitoring. The achieved level in a real machine also depends on the evaluation unit, wiring and the way the guard-locking solenoid is controlled, so the complete safety function must be validated by the machine builder.

Selection checklist

• Choose the function actuator first: guard-lock monitoring for personnel protection, door position monitoring for process protection.
• Decide between high coding level (only the taught-in actuator is accepted) and low coding level (any suitable actuator of the type is accepted).
• Check whether people can be trapped inside the guard; if so, add the escape release on the rear side.
• Confirm the 24 V DC supply is SELV/PELV and, for UL installations, a Class 2 source as EUCHNER specifies.
• Plan the M12 8-pin cable to the cabinet and the safety relay or safe input that will evaluate FO1A/FO1B.

Installation and maintenance

Mount the switch and actuator so the actuator cannot be used as an end stop for the door; a separate mechanical stop protects the bolt. Use the fixing holes and, on aluminium profile fences, the EUCHNER mounting plate. Keep the actuator aligned within the tolerances shown in the dimension drawing, and fasten both parts with tamper-resistant screws so the interlock cannot be defeated easily. After installation, test every function: door open, door closed but unlocked, locked, auxiliary release and escape release. In service, inspect the switch at regular intervals for damage, loose fixings and dirt in the actuator entry, and repeat the functional test. The IP69K rating allows high-pressure washdown, but cleaning agents should be compatible with the thermoplastic housing.

Typical applications in Oman and the GCC

The CTS-C1-BP-CC-FLX-AP-USA suits machine guards in packaging lines, food and beverage plants, robot cells, palletisers and process skids where a compact switch with high holding force is needed. Its washdown rating fits hygienic plants, and the small housing fits narrow aluminium profile doors used by machine builders across the region.

Why source from Seven Star LLC

Seven Star LLC supplies EUCHNER safety switches and accessories across Oman and the GCC. Send us the order number, the function actuator and any accessories, and our team can help confirm the correct ordering code before you request a quote.