DQE Series Safety Light Curtain Sensor and Safety Relay Connection Guide

The main link between safety light curtains and safety relays in the modern industrial automation system, and the reliable safety, is vital to the safe function of human and equipment. As such these safety light curtains are used extensively in stamping, machining, automated assembly line, etc in various situations.

DAIDISIKE series safety light curtains have dual OSSD outputs, noise-resistant design as well as interfacing with many safety relays that can be used. DAIDISIKE DQE Series Safety Light Curtains are broadly used such as in stamping, machining, automated assembly lines, and other applications. We have detailed in this article the connection principle and we will take a brief step in each step, examples, and key consideration of both the DQE series safety light curtains and safety relays to fast get the wiring compliance in order to complete the safety compliance in less time.

I. Principles and Prerequisites of Connectivity core.

In addition, it operates through two OSSD (Output Signal Switching Device) outputs. When it is triggered, outputs via EDM (External Device Monitoring) function are supported, and the equipment complies with IEC 61496-1 Type 4, PL e/SIL 3 safety level. Safety relay (e.g. DA31, DQSRN series): As the safety control core, it takes OSSD signal from the light curtain to block out power circuit with a pair of safety contacts and simultaneously EDM feedback checking to prevent the exposure hazard caused by contactor contact welding and the other faults.

II. General Wiring Process (use dual OSSD+EDM as a case in point)

1. Preparation before wiring

Unplug power supplies, check the line with a multimeter through and through so as not to short-circuit; Matching up DQE light curtain cables based on the wiring diagram (brown: +24VDC, blue: 0V, white: OSSD1, black: OSSD2, yellow-green: shielding ground); The safety relay was mounted on the 35mm DIN rail and the heat dissipation space was ≥5cm.

Step-by-step wiring

(1) Power connection DQE light curtain power supply: brown wire to 24VDC positive (series 5A fuse), blue wire to 24VDC negative safety relay power supply: the corresponding terminal (+) which is connected to 24VDC positive, (0V) which is connected to 24VDC negative, so the power supply has ripple ≤10%.

(2) The OSSD signal connection (dual redundancy) DQE light curtain white line (OSSD1) → safety relay channel 1 input terminal (as shown below S1); DQE light curtain black line (OSSD2) → safety relay channel 2 input terminal (S2), and, if the light curtain is NPN output type, common terminal of the safety relay input is connected to the negative terminal of 24VDC; If it is PNP type, common terminal (CP) is connected to positive terminal of 24VDC (see wiring logic of DQSRN series).

(3) EDM Feedback Circuit Connection safety relay EDM output terminal (T1/T2) → contactor auxiliary normally closed contact (K1/K2 in series); other side of the contactor contact → DQE Light Curtain EDM input terminal (some models have multiplexed OSSD common terminal, review manual). At the other end of the contactor contact → DQE Light curtain EDM input terminal (a number of models multiplexed are OSSD common terminal; product manual); Role of check: To check on contactor contact state, after contact is melted and welded the EDM signal should be abnormal, after the light curtain is in alarm mode, it should prohibit reset.

(4) Reset function connection Manual reset button (two keys anti-false-touch, SR and SRC) → Safety relay reset terminal (SR) and reset control terminal (SRC). SR and SRC shorted, for automatic reset and disconnected for manual reset (manual reset must be configured according to the scenario, manual reset is recommended, particularly if risks are high).

(5) Shield and ground DQE light curtain yellow-green shielding line → safety relay grounding terminal and then single-ended grounding (cabinet grounding row, grounding resistance ≤ 4Ω); signal line and power line spaced ≥ 200mm, vertical cross-wiring designed to prevent electromagnetic interference.

Sample Connection (DAIDISIKE Safety Relay Adapted)

Example 1: DQE series (PNP type) + DA31 series safety relay

Example 2: DQE series (NPN type) + DQSRN series safety relay (2 outputs)

Power supply connection: same as Example 1, safety relay CP terminal connected to 0V; OSSD signal: OSSD1→S1, OSSD2→S2, to ensure the synchronisation of the two signals; Safety output: relay 23/14, 33/43 (NO contact) to contactor coil, 41/42 (NC contact) to alarm indicator; Wiring diagram for reference: DQSRN Series 2-Channel Safety Output Wiring Diagram, strictly matching the terminal identification.

Check Before Power-on

Verify that the wiring is correct according to the schematic diagram and does not reverse or short circuit; Use a multimeter to measure the voltage of the power supply terminals and ensure it is 24VDC±10%; Check if the grounding of the shield is good, no overhang. Ensure that the shielding layer is properly grounded and there is no overhang.

Functional debugging

No blocking state: DQE light curtain OSSD1/OSSD2 output high level, safety relay indicator green light is always on, the safety contact is closed; blocking test: blocking the light curtain, OSSD1/OSSD2 out of step, the relay immediately trips, the safety contact is disconnected, the alarm indicator light is on. EDM failure test: analogue contactor contact welding (shorting K1), the relay cannot be reset, the light curtain maintains the alarm state; reset test: after lifting the masking, manually press the reset button, the relay returns to normal, and the safety contact closes.