The application of multi-period long delay time relay in the field of automatic control
Overview In the field of time control, the delay specification of the control time is usually selected according to the controlled time and the accuracy of the time delay. In order to ensure the reliability of the delay precision, the maximum delay range of the time relay delay should generally be consistent with the time required by the controlled appliance (especially the time relay set by the knob). Only in this way can the relay reach the corresponding minimum setting error , So as to better control the controlled circuit and device more effectively and accurately.
In order to meet the control of multiple time periods (usually the time delay setting of the time relay is single and can only meet the control of a specific time period), there are multiple time delay periods in the time relay, only the time relay delay nameplate and adjustment The override selection switch can meet the above multi-period control without adjusting the internal delay circuit. Specifically, this product can replace multiple products, which is more convenient for users to choose and use, and saves users control costs; and the manufacturer has therefore made the time relay model and delay specifications more reasonable and simplified. In short, this multi-time relay meets the characteristics of multi-function, miniaturization and cost saving in the control field, which is the development trend of the time relay field.
At present, the domestic JSZ3 series of time relays have the functions of multiple time periods (AA, B, C, D, E, F, G, seven specifications, 28 kinds of delay periods), long delay (0.05s ~ 24h), which is an alternative to ST3P (Japan Fuji) Ideal product for time relays. This series of products has been widely used in a variety of control fields due to the advantages of wide delay range, high delay precision, good reliability, long life, small size, and convenient setting time.
Time relay built-in chip chip pin
At present, there are many models of the built-in delay chip of the time relay: F6445C, RS6445C, LM8445, QA640896, etc. The above models are mainly distinguished from the package form (single in-line and double in-line) and the internal logic functions are the same. The following uses F6445C as an example:
Pin introduction FIN—frequency input terminal: there is a voltage comparator in this terminal, which can form an oscillator with an external resistance-capacitance network to generate the main clock signal;
ADJ—voltage adjustment terminal: the adjustment level added at this terminal and the window comparator, discharge circuit and RS flip-flop inside the circuit together form the main oscillator, which can easily adjust the main frequency;
VDD, VSS—positive and negative terminals of power supply;
A, B-level preset terminal: frequency division selection terminal, the switch is suspended (or connected to the pull-down resistor) for low level (L), and connected to VDD for high level (H);
TEST—The test terminal (the test terminal is grounded or floating, if the external clock signal test terminal is connected to high level) is a bidirectional output input terminal, which can be used by the user when debugging the system. Under normal working conditions, "TEST" is floating, and it is the output terminal, which outputs the 1024Hz square wave signal of the main vibration circuit, which can be measured with an oscilloscope and a frequency meter;
OUT-output: output high level to drive relay contact switching, at this time the oscillator stops working and the discharge circuit is disconnected.
Preset circuit settings
Set time T = 2/3 × 1024 × N × R * •• C * where R * • C * are delay potentiometer and delay capacitor respectively, and N is frequency division factor.
Delay period and specifications (Table 2)
The multi-time relay has a total of 7 specifications (AA, B, C, D, E, F, G), 28 delay sections, each specification has 4 delay sections, and the specification period consists of 2 nameplates (each positive and negative) There are two delay sections). According to the required control period, remove the delay knob and select the corresponding nameplate.
Delay setting Take the AC specification time relay as an example:
T = 2/3 × 1024 × N × R * • C * = 2/3 × 1024 × 1 × 800 × 103 × 10000 × 10-12 = 5.46 (S)
Based on AC specifications, N = 1 (terminal A 5; terminal B 4)) are connected to high level "H" for other periods. On this basis, the frequency division factor N can be set to 10, 60, 360 respectively The delay time of the other three periods of this specification (make A and B connected to "H" or "L" as required, see Table 1).
Working principle analysis
Principle analysis External working power supply AC220V, and connect RU varistor at the power input port (absorb harmonic interference in the working power supply). After V1 half-wave rectification, the relay KA is connected all the way, the other is filtered by R8 and C4, and then added to the voltage regulator VZ through R7, LED2 and R6, and C2 and C3 are connected to the voltage regulator in parallel to ensure stable DC The voltage is used by the circuit chip. The external resistance-capacitance network of the FIN terminal generates the main frequency of oscillation. After a fixed frequency of 1024Hz, it is divided by 1, 10, 60, and 360 according to different frequencies (see Table 1 for the settings of the A and B ports according to the requirements). After the internal composite circuit matches (reaches the set delay), OUT outputs a high level to turn on the thyristor, the internal electromagnetic relay KA coil pulls in, and the contacts are switched to control the external circuit; while OUT outputs a high level, In order to make the chip internal RS set, the oscillation stops.
Conclusion Multi-period long delay time relay, because of its convenient time period selection (replacement of random nameplate) can meet the requirements of delay control (single product can meet 4 time periods), plus the product time setting is convenient, widely used Used in the field of automatic control timing of machine tools and various equipment.
Excellent metal material, which guarantees durability.
Processed by precision machine tool, standard G1/4 screw thread with good compatibility.
Electroplating on the surface, anti-oxidization and resistant to corrosion.
Mature sealing process, high-quality sealing components, safe, leakage-proof, and more reliable.
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