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In level measurement, users often face the problem of having to select the sensor’s output so that the control room can monitor and control the level. Currently, the common signal output types for sensors include the following five: relay output, two-wire output, transistor output, contactless output, and NAMUR output. In the field of level measurement in China, relay output is the most widely used, followed by two-wire output, while NAMUR output is the least used. According to the working principle of the NAMUR output (for details, please visit http://www.levelmeter.cn/baikeshow-87-758-1.html), the NAMUR output operates using low-voltage power supply and a micro-current output; similar to the two-wire output, it is used only in hazardous areas where explosion protection is required. In the field of level measurement in our country, products with NAMUR output are rarely used. Only a very small number of users who initially used imported level measurement products (especially those imported from Germany) chose some products with NAMUR output, such as fork-type level switches, due to their temporary admiration for imported products. Regrettably, due to their lack of understanding of NAMUR output technology and its applications, these individual users, when it comes to product maintenance, replacement, or upgrading and the need to use domestic products as substitutes for those with NAMUR outputs, often mechanically insist that the substitute domestic products must meet NAMUR output standards. In fact, there is no need to insist on using the NAMUR output method. Firstly, the NAMUR output method is not irreplaceable; secondly, products using this output method are expensive, and it would be unreasonable to pay such a high price. So, how can domestic level switches be used to replace these imported NAMUR-output products? To replace products with NAMUR outputs, we can entirely use commonly available domestic two-wire output products as substitutes. This is because the two-wire output, like the NUMUR output, is also a passive two-wire system; the main difference lies in the magnitude of the output current. This difference does not prevent level measurement products with a two-wire output from fully replacing NAMUR output products in explosion-proof applications. The similarities between the two-wire output method and the NAMUR output method are as follows: Both belong to the passive two-wire system, meaning that the two wires serve both as power lines and signal lines; there is no separate power supply, as the safety barrier provides power to the sensor, and the signals transmitted are passive signals. Both determine the level by means of current signals; they both convert the switch signals using isolation gates and then transmit them to the DCS or PLC control room. Differences between the two-wire output method and the NAMUR output method: 1. The safety barrier used in conjunction with NAMUR sensors provides 8VDC power to those sensors, whereas the safety barrier used with the two-wire output provides 24VDC power. In comparison, there are more options available for safety barriers that provide 24VDC power, whereas there are relatively fewer options for those that provide 8VDC. 2. The detection points for NAMUR output are usually ≤1.2mA and ≥2.1mA (the values vary depending on the manufacturer), while the detection points for two-wire output are generally 8mA and 16mA. Based on the comparison of the data above, all the values for NAMUR are lower than those for the two-wire system. However, in the field of level measurement, the various performance indicators of the two-wire system meet the requirements for intrinsically safe explosion protection, eliminating the risk of igniting explosive gases or dust and causing an explosion. It is precisely because NAMUR uses lower currents and voltages that it imposes higher requirements on the circuit design and the electronic components used, as well as lower power consumption requirements; this will undoubtedly lead to a significant increase in product prices. Furthermore, in China, the use of NAMUR output in level measurement is extremely rare, and there are few technicians who are familiar with this type of output. As a result, the cost of maintenance becomes very high in the event of any problems. Currently, the price of level switches with a two-wire output method, which are widely used in China, is only a fraction of those with NAMUR output. In the field of level measurement in China, the NAMUR output method is rarely used, while the two-wire output method is more commonly employed. Therefore, in level measurement, using two-wire output products in place of NAMUR output products is not only entirely feasible in theory but also highly necessary in practice. Level switch products that use a two-wire output method can meet users’ explosion-proof requirements while significantly reducing their purchasing costs; they are also more economical in terms of use and maintenance. This replacement is also very simple; it only requires replacing the isolation barrier together. For example, for existing installed fork-type level switches, two-wire output fork-type level switches along with their corresponding safety barriers can be used to replace the existing NAMUR-output fork-type level switches and their associated safety barriers.