Shocking revelation: This intrinsically safe explosion-proof display alarm can be used in Zones 0, 1, and 2

Thread Content

. Preface: There is a type of “advertising” called preaching, haha. Are scientific discoveries and technological achievements beneficial to humanity? 1. This product – the intrinsically safe explosion-proof display alarm – might be another innovation created by our village’s Shuaike Sensing Instruments Manufacturing Company; it features a world-first design. Its working principle is simple, and the design itself isn’t very complex. I’m sharing it with everyone for two reasons: first, I hope it can be useful to everyone; second, I welcome those who are skilled enough to imitate it, as well as colleagues who might copy it, haha. After all, technology belongs to all of humanity – we don’t bring it with us when we’re born, nor do we take it with us when we die, right? 2. The intrinsically safe explosion-proof display and alarm instrument is a type of intrinsically safe device that can be installed and used directly in explosion-proof zones 0, 1, and 2, and it can be calibrated while still powered on. Its explosion-proof rating is the highest level within the intrinsically safe category, namely E*aⅡCT6. It is a two-wire instrument that uses a 4/20mA signaling system for alarms – which is an innovative approach, isn’t it? As for the various display and alarm devices available on the market, they are almost all multi-wire devices that use relays for signaling alarms. Due to their high power consumption, it is difficult for them to achieve intrinsically safe performance. So what does a 4/20mA alarm signal mean? It means that the intrinsically safe explosion-proof display alarm device always outputs a 20mA signal when an alarm is triggered, and always outputs a 4mA signal when the alarm is cleared. For the working principle diagram, see: The method for setting the alarm parameters of the intrinsically safe display alarm device is similar to that of ordinary display control devices available on the market. For example, the type of alarm can be set as an upper limit alarm, a lower limit alarm, or an alarm for exceeding both limits. Although the 4/20mA system supports only one alarm channel, since the device allows for alarm control based on large range variations, the upper and lower limit settings can be managed using just one signal channel. For instance, an alarm can be triggered when the liquid level drops to 1 meter, with a 20mA signal being output; the alarm is then cleared when the liquid level rises to 15 meters, with a 4mA signal being output. Similarly, an alarm is triggered when the pressure rises to 0.8MPa, with a 20mA signal being output, and the alarm is cleared when the pressure drops to 0.4MPa, with a 4mA signal being output. Another example is when the water temperature exceeds 40°C or falls below 20°C, an alarm is triggered with a 20mA signal; the alarm is cleared when the water temperature is between 20°C and 40°C, with a 4mA signal being output. 3. Since the intrinsically safe explosion-proof display alarm device uses a two-wire current-based alarm system, it can only provide one alarm output signal. When multiple alarms are needed, several such devices can be connected in series within the 4–20mA current circuit, as shown in the diagram. 4. Some engineers are very resourceful; they use a 100Ω resistor to capture the 4/20mA alarm signals and integrate them into the control system. Other electricians, however, prefer to use relay signals. In such cases, they need to spend a little extra money to purchase a module that converts the 4/20mA alarm signals into relay outputs. This relay module is passive – it can be inserted anywhere in the current circuit and operates without requiring separate power supply. In other words, it can be used in both safe areas and explosion-proof areas, either installed in flameproof boxes or enclosures. Flexibly deciding where to place the module can save a lot of money on cables, as the savings might be many times greater than the cost of the module itself. 5. The display accuracy of the intrinsically safe explosion-proof display alarm device is ±0.02%. Note that this refers to two ten-thousandths, not two thousandths. The display screen is a 5-digit backlit LCD screen with a resolution of approximately 1/60,000. 6. In addition to the alarm functions mentioned above, the intrinsically safe display alarm device can also be used as a manual regulator or as part of a programmable fully automatic regulating system. This will be discussed in more detail in a separate post