The Panic Button requires an interference signal to be completely filtered
It is not possible to use the Panic Button to completely filter the conducted jamming signal. Because the interference signal spectrum is very wide, basically covering the tens of thousands of twigs to hundreds of megahertz or even gigahertz on the frequency range. General low-end interference signal, the filter requires a large capacity of the filter capacitor, but by the security conditions, the capacity of the capacitor can not be too large; and high-end interference signal filtering, large-capacity capacitor filtering performance is very poor , Especially the high frequency performance of polyester film capacitors are generally poor, and the high frequency response characteristics of polyester film media are very different from those of ceramics or mica. In addition, the general polyester film medium has the adsorption effect, so it Will reduce the operating frequency of the capacitor. Polyester film capacitor operating frequency range is about 1MHz or so, more than 1MHz when the impedance will be significantly increased.
Panic Button on each IC and then a 0.01μF ~ 0.1μF high-frequency capacitors to reduce the impact of IC on the power supply. But should pay attention to the Panic Button high-frequency capacitor wiring, wiring should be close to the power side and as thick as possible, otherwise, equal to increase the capacitance of the equivalent series resistance, which will affect the filtering effect. The relay coil increases the freewheeling diode to eliminate the backlash interference generated when the coil is disconnected. In the relay contact at both ends of the spark suppression circuit (usually RC series circuit, the resistance is generally selected several thousand euros to tens of thousands of euros, the capacitor selected 0.01μF, to reduce the impact of spark.
In order to prevent both ends of silicon control and RC RC circuit, reduce the noise generated by thyristor, the noise may be serious when the thyristor breakdown. AC end with inductance capacitor filter: remove the high frequency low frequency interference pulse, VCC and GND asked the electrolytic capacitor and ceramic capacitors to remove high and low frequency interference signal. To prevent the control board circuit generated by the conduction interference can be in the circuit into the population (that is, AC at both ends and connected to a capacitor C, shown in Figure 1 is a simple capacitor interference circuit connection diagram. The capacitor is an Panic Button, But a safety resistor must be connected in parallel at both ends of the capacitor to prevent the power cord from being energized for a long time when the power cord is plugged in. Because the safety standard states that when the machine power cord is in operation, The voltage (or ground potential must be less than 30% of the original voltage) at both ends of the power cord.
Panic Button why the bus and sub-line, take the Panic Button for methane, the middle of what is the difference? Bus and sub-line is the main way of wiring, most of the sub-line-type instrument for the three-wire system, the detector and the host channel are one by one, each detector must be connected to a three-core to the host. Detection of flammable and detectable toxic Although the price difference between the poor, but the use is certainly not the same. And industrial safety norms marked on the plain, ammonia is a toxic gas, ammonia must be tested the toxicity, that is, according to ammonia ppm detection. In some places, if the user is installing the flammable ammonia Panic Button, the local quality supervision bureau is not checked, so the user must pay attention when selecting the Panic Button. For safety instruments, the ammonia Panic Button is not only a device, but also a safety device, is a protective work of industrial safety, so I suggest that users do not just because of its cheap and buy, to our personal Security is responsible. Purchase time to see the relevant hard technical parameters.
For most of the bus-type Panic Button, for the four-wire connection, four-wire connection by the host cited a main line out, and then the various detectors were connected to the main line above the main line. For the choice of Panic Button bus and sub-line, mainly by the user to select the number of detectors to determine the number of detectors for more than 6, then the general use of the bus Panic Button. If you have less than six, you must use sub-line Panic Button. Detector to avoid high concentrations of ammonia impact, so the detector is easy to poison; to avoid frequent power, power supply instability, so easy to damage the instrument. Often the detector is wiped to prevent dust from clogging the sensor. The necessity of the detector calibration prevents the detector from detecting data wandering and improving the accuracy of the detector data. Detector is regularly calibrated, components are protected, and the service life is long. Detector calibration is generally used in the last year or six months after the on-site inspection environment. Panic Button detection environment is generally affected by dust, corrosion and other related effects of ammonia, the environment is relatively poor, so the user in the use of time to the Panic Button to maintain, so as to maximize the efficiency of Panic Button detection and long life, The cost.