Working principle of PILZ relay PILZ 750111

PILZ 750111 (PNOZ s11 24VDC) is a multi contact extended safety relay of the PNOZsigma series. Its core features include 8 safety normally open contacts and 1 auxiliary normally closed contact. It adopts a modular design and is compatible with 24V DC power supply. It has high anti-interference, high reliability, and compact structure, and strictly complies with ISO 13849-1 PL e/Cat.4 and IEC 61508 SIL 3 safety standards. It is designed for harsh working conditions such as high temperature, high dust, strong electromagnetic interference, and multi equipment linkage in the steel industry. It is widely used in the entire production process of steelmaking, rolling, coking, sintering, etc. It is the core control and expansion component of the safety circuit in the steel industry, providing reliable guarantee for personnel, equipment, and production continuity. PILZ 750111 imported from Germany is in stock and will be shipped on the same day.

1、 Core technical parameters (adapted to the working conditions of the steel industry)

### 1. Basic electrical and structural parameters

The model is 750111 (PNOZ S11 24VDC 8 n/o 1 n/c), with a power supply voltage of 24V DC, an allowable fluctuation range of -15%/+20%, and a power consumption of 2W, meeting the requirements of unstable voltage scenarios in steel workshops. The input configuration is dual channel independent input, compatible with normally open and normally closed contact type safety devices, supports short circuit detection between contacts, and can be directly connected to safety components such as emergency stop buttons, safety door switches, and gratings. The output configuration includes 8 safety normally open contacts and 1 auxiliary normally closed contact, with contact specifications of AC15 240V/5A and DC13 24V/4A. It adopts a forced guiding structure to eliminate the risk of contact adhesion and can simultaneously control the safety circuits of multiple devices.

The physical size is 22.5mm ultra-thin width, installed on a 35mm DIN rail, and designed with pluggable screw terminals for easy installation, wiring, and maintenance. The working temperature range is -10~55 ℃, the protection level is IP20 (terminal)/IP40 (shell), the anti vibration is 10-55Hz/0.35mm, and the anti electromagnetic interference ability meets the EN 55011 standard. It can adapt to the harsh environment of high temperature, dust, vibration, and strong electromagnetic radiation in the steel workshop, ensuring long-term stable operation.

### 2. Core parameters of security performance

Compliant with international safety standards such as EN 60204-1, EN 60947-5-1, ISO 13849-1, IEC 61508, etc., the safety level reaches ISO 13849-1 PL e/Cat.4, IEC 61508 SIL 3, meeting the safety control requirements of high-risk equipment in the steel industry. Built in full cycle self detection function, real-time monitoring of input short circuits, contact adhesion, channel faults, power supply abnormalities, etc. Once a fault is detected, the safety output is immediately cut off, the equipment is forced to shut down, and dangerous outputs are eliminated.

Fast response speed, input-output response time ≤ 20ms, suitable for high-speed shutdown requirements of steel equipment, avoiding equipment damage, material loss, and safety accidents. Supports two modes of manual reset and monitoring reset, which can be flexibly configured according to on-site safety logic. After troubleshooting, the reset operation must be completed before the device can be restarted, ensuring on-site safety and controllability. The panel integrates power, channel, output, and fault LED indicator lights to visually display the device's working status and fault type, making it easy for on-site operation and maintenance personnel to quickly troubleshoot problems.

##2、 Core application scenarios in the steel industry

### 1. Steelmaking workshop: safety control of high-temperature and high-risk equipment

Converter and electric furnace are the core equipment in the steelmaking workshop, with high temperature and high dust in the working environment, and there is a risk of steel splashing and equipment misoperation. The 750111 safety relay serves as the core control component, monitoring the emergency stop buttons, safety doors, furnace limit switches, and cooling water pressure detection signals of the converter and electric furnace. Once an abnormality is detected, the power supply to the main motor, tilting mechanism, and feeding mechanism of the equipment is instantly cut off, forcing the equipment to shut down and preventing accidents such as steel splashing and furnace overturning.

Its 8 safety outputs can simultaneously control the safety circuits of the converter dust removal system and cooling water system, achieving multi device linkage safety control, ensuring synchronous shutdown of auxiliary equipment during the steelmaking process, and avoiding secondary risks. At the same time, through the self detection function, the real-time monitoring of the circuit status can detect problems such as line faults and contact adhesion in a timely manner, reduce downtime caused by faults, and ensure the continuity of steelmaking production.