German PILZ safety relay selection and working principle introduction

1. First understand the necessary conditions
1 control circuit power supply voltage, the maximum current that can be provided;
2 voltage and current in the circuit being controlled;
3 The controlled circuit needs several sets and what forms of contacts. When a relay is selected, the power supply voltage of the general control circuit can be used as the basis for selection. The control circuit should be able to provide sufficient operating current to the relay, otherwise the relay pull-in is unstable.
2. After consulting the relevant data to determine the conditions of use, you can find the relevant information and find the model and specification number of the required relay. If there is a relay on hand, you can check whether it can be used according to the data. Finally consider whether the size is appropriate.
Pilz safety relay, Germany Pierzi safety relay
The principle of PILZ safety relay PILZ safety relay is generally composed of iron core, coil, armature, contact reed and so on. As long as a certain voltage is applied to both ends of the coil, a certain current flows through the coil, thereby generating an electromagnetic effect, and the armature absorbs the tension of the return spring against the tension of the return spring under the attraction of the electromagnetic force, thereby driving the armature. The moving contact is in contact with the stationary contact (normally open contact). When the coil is de-energized, the electromagnetic suction force also disappears, and the armature returns to the original position in the reaction force of the spring, so that the movable contact and the original static contact (normally closed contact) are attracted. In this way, the suction and release are achieved, thereby achieving the purpose of turning on and off in the circuit. For the "normally open, normally closed" contacts of the relay, it can be distinguished as follows: a static contact that is in an open state when the relay coil is not energized, called a "normally open contact"; a static contact that is in an on state It is a "normally closed contact".
Pilz Germany PILZ safety relay selection and working principle
The working principle and characteristics of PILZ safety relay:
The PILZ safety relay is a new type of thermal switch that uses temperature sensitive magnetic materials to detect and control temperature. It consists of a temperature-sensitive magnetic ring, a constant magnetic ring, a reed switch, a thermally conductive mounting piece, a plastic substrate, and other accessories. The thermal reed relay does not use coil excitation, and the magnetic force generated by the constant magnetic ring drives the switching action. Whether the constant magnetic ring can supply the magnetic force to the reed switch is determined by the temperature control characteristics of the temperature sensitive magnetic ring.
3. Working principle and characteristics of PILZ safety relay (SSR):
The PILZ safety relay is a four-terminal device with two terminals as the input and the other two as the output. The isolation device is used to realize the electrical isolation of the input and output.
PILZ safety relays can be divided into AC type and DC type according to the type of load power supply. According to the switch type, it can be divided into normally open type and normally closed type. According to the isolation type, it can be divided into hybrid type, transformer isolation type and photoelectric isolation type, and the photoelectric isolation type is the most.
2. PILZ safety relay DC resistance refers to the DC resistance of the coil in the relay, which can be measured by the universal meter.
3. PILZ safety relay pull-in current refers to the minimum current that the relay can generate the pull-in action. In normal use, the given current must be slightly larger than the pull-in current so that the relay can operate stably. For the working voltage applied to the coil, generally do not exceed 1.5 times the rated working voltage, otherwise a large current will be generated and the coil will be burnt.
Pilz Germany PILZ safety relay selection and working principle
The PILZ safety relay coil is indicated by a long square symbol in the circuit. If the relay has two coils, draw two long square boxes. At the same time, the relay's text symbol "J" is marked in the long box or next to the long box. There are two ways to represent the contacts of a relay: one is to draw them directly on the long square side, which is more intuitive. The other is to draw the respective contacts into their respective control circuits according to the needs of the circuit connection. Usually, the same text symbols are marked on the contacts and coils of the same relay, and the contact groups are numbered. To show the difference. There are three basic forms of relay contacts:
1. When the moving type (H type) coil is not energized, the two contacts are disconnected. After energization, the two contacts are closed. It is represented by the pinyin head "H" of the word.
2. When the breaking type (D type) coil is not energized, the two contacts are closed, and the two contacts are disconnected after energization. It is represented by the pinyin head "D" of the hyphenation.
3. Conversion type (Z type) This is the contact type. This contact group has three contacts, that is, the middle is a moving contact, and one static contact is provided. When the coil is not energized, the movable contact and one of the static contacts are opened and the other is closed. After the coil is energized, the movable contact moves, so that the original disconnection is closed, and the original closed state is turned off, and the conversion is achieved. purpose. Such a set of contacts is called a changeover contact. It is represented by the pinyin head "z" of the word "turn".