How to use Pilz's safety relay PNOZ S4

In the previous article, we have introduced Pilz's safety relay PNOZ X3 andX2.7P/2.8P, (Reference: How to use Pilz's safety relay PNOZX2.7P/X2.8P? ) Today’s article, let’s introduce another safety relay product PNOZ s4.

PNOZ s4 can be used for emergency stop buttons, safety doors, safety switches and other occasions. Let's take a look at its appearance first:

In the above picture, the left is the photo with the front cover closed; the right is the photo with the front cover opened.

The front panel of PNOZ s4 has 6 LED indicators to indicate the corresponding status:

When the power supply is normal, the Power light is always on;

When the safety channel 1 is closed, the In1 light is always on;

When the safety channel 2 is closed, the In2 light is always on;

When the safety contact is closed and Y32 has a level output, when S34 has a reset input signal, the Reset light is on;

When there is an external fault, the Fault light is always on; when there is a PNOZ s4, there are 8 connection terminals on the upper and lower sides, of which:

A1 and A2 are power connection terminals;

S11 and S12 are the wiring terminals of safety channel 1;

S21 and S22 are the wiring terminals of safety channel 2;

S34 is the reset/start terminal;

Y32 is the output terminal;

13-14, 23-24, 33-34 are three groups of safe normally open contacts;

41-42 is a set of auxiliary normally closed contacts;

PNOZ s4 has two power supply voltages: 24V DC (order numbers: 750104, 751104, 751184) and 220V AC (order numbers: 750134, 751134), which can be selected according to the needs of the project. Each product has two safe channels; three safe normally open contacts and one auxiliary normally closed contact; the following picture is the internal circuit diagram of PNOZs4 (DC 24V):

The two safety channels of PNOZ s4 can be connected as a single-channel type (without short-circuit detection between contacts) or a dual-channel type; the dual-channel type can be divided into a type with short-circuit detection between contacts and a type without short-circuit detection between contacts Type; the figure below is the wiring method of emergency stop button without short circuit detection between contacts:

The following figure is a schematic diagram of dual-channel wiring of a safety door with short circuit detection between contacts and an emergency stop button:

Let's talk about the reset/start function of PNOZ s4. The safety relay supports the following reset/start methods:

Automatic reset/start (automatic start);

Manual reset/start (manual start);

Falling edge monitoring reset/start (Mornitored start with falling edge);

Rising edge detection monitor reset/start (Mornitored start with rising edge);

Start with start-up test (Start with start-up test);

In automatic reset/start mode, when the safety channel is closed, the safety relay will automatically be ready; in manual reset/start (manual start) mode, when the safety channel is closed and the start circuit is closed, the safety relay will Ready

In the morning start with falling edge mode, when the safety channel is closed, and the start circuit is closed and then opened, the safety relay will be ready;

In Mornitoredstart with rising edge mode, when the safety channel is closed and the start circuit is closed for a certain period of time, the safety relay will be ready; Start with start-up test mode Mostly used for safety doors, the safety relay will detect the open and closed state of the door; The mode can be set by the mode selection button on the front of PNOZ s4, as shown below:

The meaning of the mode selection switch is shown in the following table:

The wiring of the reset circuit includes two modes with feedback circuit and without feedback circuit. The schematic diagram is as follows:

Okay, let’s talk about Pilz’s PNOZ s4 safety relay first.