How to use Pilz's safety relay (There is a wiring diagram inside)

A good control system must first be a safe system-in the event of a system failure or emergency shutdown, it can ensure the safety of people and equipment. When it comes to safety automation systems, we have to mention the German company Pilz. Pilz has been deeply involved in the field of safety automation for decades and has many safety products such as safety PLCs, safety switches, and safety relays. The most worth mentioning is that Pilz made the first safety relay (PNOZ) for emergency stop, which has been widely recognized worldwide. Since then, PNOZ has almost become synonymous with safety relays. Today, PNOZ safety relays have many series of products, such as: PNOZsigma, PNOZX, PNOZcompact, PNOZelog, etc., and there are different models under each series. In today's article, we take PNOZ X3 as an example to talk about the use of safety relays for emergency stop buttons.

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The appearance of PNOZ X3 is as follows:

Encoder|Transmitter|Soft starter|Power supply|VFD|Light curtain|Servo products|Human-machine interface|Solenoid valve|Cylinder|Actuator|Flow meter|Transformer|Thyristor|Sensor|Deceleration drive gearbox reducer|Linear guide|Circuit breaker|Refrigeration compressorAll industrial products of okplazas are purchased from the original factory or formal channels of agents to ensure the original authenticity, which perfectly solves the problem of industrial product sample procurement and small-batch procurement for the majority of engineers and purchasing personnel.

PNOZ X3 has three safety contacts: 13-14, 23-24 and 33-34, all of which are normally open contacts and can be used for safety circuits; there is one auxiliary contact, 41-42, which is normally closed contact point. Auxiliary contacts cannot be used in safety circuits; there is a transistor output contact: Y31-Y32.

PNOZ X3 has 10 safety circuit terminals, whose names all start with "S" (Safe), including S11, S12, S13, S14, S21, S22, S31, S32, S33 and S34. among them

S11 and S13 are internally connected to the positive pole of the power supply, and S21 is internally connected to the negative pole of the power supply. Two safety channels (CH1 and CH2) and a start/reset channel (Start Unit) are connected inside the S terminal. The following picture is the internal wiring diagram of PNOZ X3:

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PNOZ X3 can accept 230V AC or 24VDC two power sources. When connecting 230V AC, A1 connects to L1, A2 connects to N, and B2 connects to ground; when connecting 24V DC, B1 connects to the positive pole (+24V), and B2 to the negative pole. As shown below:

Encoder|Transmitter|Soft starter|Power supply|VFD|Light curtain|Servo products|Human-machine interface|Solenoid valve|Cylinder|Actuator|Flow meter|Transformer|Thyristor|Sensor|Deceleration drive gearbox reducer|Linear guide|Circuit breaker|Refrigeration compressorAll industrial products of okplazas are purchased from the original factory or formal channels of agents to ensure the original authenticity, which perfectly solves the problem of industrial product sample procurement and small-batch procurement for the majority of engineers and purchasing personnel.

There are three LED indicators on the front of PNOZ X3, which indicate power (POWER), channel 1 (CH.1) and channel 2 (CH.2). When the power is turned on, the POWER LED light Is lit (green); when the power is turned on and the safety channels S13-S14 are in a closed loop,PNOZ X3 is ready to work (Ready);

At this time, if both channel 1 (CH1) and channel 2 (CH2) are in a closed loop, the safety normally open contacts 13-14, 23-24 and 33-34 are closed, and the auxiliary normally closed contacts 41-42 are disconnected; The LED lights of both channels are lit (green); transistor outputs Y31-Y32 are closed; at this time, if channel 1 (CH1) and channel 2 (CH2) are disconnected (for example: take the emergency stop button), it is safe The open contacts 13-14, 23-24 and 33-34 are disconnected, the auxiliary normally closed contacts 41-42 are closed; the LED lights of both channels are off; the transistor output Y31-Y32 is disconnected;

Let's take a look at how PNOZ X3 connects the emergency stop button:

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When using a single-channel emergency stop button, connect S21-S22, S32-S31, and then connect the normally closed contact of the emergency stop button between S12-S11; when using a dual-channel emergency stop button, connect S11-S12 are connected, and the two normally closed contacts of the emergency stop button are respectively connected between S21-S22 and S31-S32;

When the safety relay is just powered on or the emergency stop button is restored, it needs to be provided to the start unit of PNOZ X3

(StartUnit) a signal to make it in the active state; PNOZ X3 start includes two ways: automatic start and manual start; automatic start (Automatic Start) is to connect S13-S14 in a closed loop. In this case, when the two safety channels (CH1 and CH2) are re-closed (for example, the emergency stop button is restored), the safety relay will automatically resume its working state; manual start, or monitored start, is S33-S34 are connected in the path of a normally open contact. In this case, even after the two safety channels (CH1 and CH2) are closed again (for example: the emergency stop button is restored), the safety relay will not automatically restore its working state. When S33-S34 must be closed manually (S3 in the figure below) for a period of time

Time (typical value 35ms), and then the safety relay can resume its working state; the wiring diagrams of Automatic Start and Monitored Start are as follows:

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When PNOZ X3 is in the active state, Y31-Y32 will be closed, and you can use the following wiring diagram to transmit the status of the safety relay to the PLC;

Encoder|Transmitter|Soft starter|Power supply|VFD|Light curtain|Servo products|Human-machine interface|Solenoid valve|Cylinder|Actuator|Flow meter|Transformer|Thyristor|Sensor|Deceleration drive gearbox reducer|Linear guide|Circuit breaker|Refrigeration compressorAll industrial products of okplazas are purchased from the original factory or formal channels of agents to ensure the original authenticity, which perfectly solves the problem of industrial product sample procurement and small-batch procurement for the majority of engineers and purchasing personnel.

The internal principles and related wiring diagrams of PNOZ X3 are introduced here first.