要选择合适的安全栅外， 在 使用的时候 还要 注意以下几 点 ： In addition to selecting a suitable safety barrier in actual use, the following points should be noted when using :
同时 也是一个关键 的 问题，特别是在系统认证 被 参量认证替代后，工程商 们 尤其要注意这个问题。 First, pay attention to the capacitive and inductive reactance of cables and field equipment. Intrinsically safe explosion protection is the explosion protection of the system. In addition to the required explosion-proof level of the safety barrier , the energy storage of cables and field equipment is also a key issue , Especially after the system certification is replaced by parametric certification, the engineers should pay special attention to this problem.
Ω 。 Second, pay attention to intrinsically safe grounding. Zener safety barriers need intrinsically safe grounding. The grounding resistance should be less than 1 Ω .
不是 本安 的 线缆应 该 分开敷设在不同的线槽里， 同时还 应 该 有明显 的 标识。 Third, intrinsically safe cables and non- intrinsically safe cables should be laid separately in different trunkings, and at the same time they should be clearly marked.
的 时 侯 应 该 注意断电。 Fourth, you should pay attention to power failure when replacing .
现场总线构成简单，容易扩容，节省成本等优点 ，所以 深受工程师们的喜爱。 Because the fieldbus has the advantages of simple structure, easy expansion, and cost saving , it is loved by engineers. 是 在石化行业中却不容易被推广开。 However, it is not easy to be promoted in the petrochemical industry. 的原因 ： The main reasons are as follows:
应该 考虑的问题。 First, there are 70% -80% dangerous areas in the petrochemical industry . Explosion protection is the first issue that petrochemical automation should consider. 是同时 也制约了总线设备的容量，使现场总线的主要优点得不到 充分的 体现。 The safety barrier is an effective component for controlling field energy, but it also limits the capacity of the bus equipment, so that the main advantages of the field bus are not fully reflected.
因为 现场的特殊性，现场设备不能带电维护 ，所以 也制约了现场总线的发展。 Second, because of the special nature of the field, field equipment cannot be maintained with power on , which also restricts the development of field buses.
由于 具有防爆功能的智能仪表还 没有 普及， 因此 也是现场总线在石化行业中得不到 较 好发展的原因。 Third, because smart instruments with explosion-proof functions have not been popularized, it is also the reason why field buses have not been well developed in the petrochemical industry .