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浙大中控电源:DCS控制系统DI卡件采用24VDC还是采用48VDC?

2021-04-16 16:09:00 来源:http://www.sdjkyqyb.com/ 53

当DI采用24V DC的回路电压时,DI模块的门限电压达到18V DC或者17V DC的时候,DI卡件就认为有信号,认为现场的接点闭合了。判断1信号的检测电压一般为16.8V DC--28.8V DC,低于16.8V DC才被认为是0,部分产品品牌的1信号判断电压其至只有15V DC。但是实际上有可能现场的触点根本就没有团合,线路上的感应电压就能达到十几V DC,这就是我们通常说的干扰造成的假信号。触点并没有闭合, 但是有较高的感应电压,当达到DI卡件门限电压时就认为有1信号。
When the circuit voltage of the di module is 24 V DC and the threshold voltage of the di module is 18 V DC or 17 V DC, the di card considers that there is a signal and the contact on the site is closed. The detection voltage of judgment 1 signal is generally 16.8v DC -- 28.8v DC, which is considered as 0 only when it is lower than 16.8v DC. The judgment voltage of 1 signal of some product brands is only 15V DC. But in fact, it is possible that the contacts on the site are not agglomerated at all, and the induced voltage on the line can reach more than ten V DC, which is what we usually call the false signal caused by interference. The contact is not closed, but there is a high induced voltage. When it reaches the threshold voltage of the di card, it is considered that there is a 1 signal.
而采用48V DC回路电压的DI卡件,其1信号的门限电压为36V DC-- 52.8V DC,有的厂家会稍微低一点,但也不会太低。现场线路感应电压达到30V DC以上的情况极为少见,这就大大减少了干扰造成的假信号的出现。因此电力行业采用48V DC作为DI卡件的回路电压,而不是24V DC、36V DC,这是根据现场实际及应用经验总结出来的结果。那为什么不选60V DC或者110V DC呢?选择一个合理的门槛,能够解决主要问题就是合适的解决方案,所以DI卡件的查询电压选到48V DC较为合适。
For the di card with 48V DC loop voltage, the threshold voltage of 1 signal is 36V dc-52.8v DC. Some manufacturers will lower it a little, but not too low. It is very rare that the induced voltage of field line reaches above 30V DC, which greatly reduces the false signal caused by interference. Therefore, the power industry uses 48V DC as the loop voltage of Di card, rather than 24 V DC and 36 V DC, which is the result summarized according to the field practice and application experience. Then why not choose 60V DC or 110V DC? Choosing a reasonable threshold can solve the main problem is the appropriate solution, so the inquiry voltage of Di card is 48V DC.                                   浙大中控电源
24V DC的DI信号回路还存在信号衰减的问题。现在流行集中控室的概念,上万根电缆都接入集中控室。 互相干扰很严重, 电缆敷设距离无形之中变长了,电缆越长越容易衰减,因为线阻会加大很多。理论上24V DC的线路可以支撑500m的距离,但是实际上现场问题都比较复杂,很多时候电缆敷设三四百米的时候电压就已经衰减的明显了,再加上如果电缆本身指标不够,那衰减会更严重。 结果是,本来信号闭合了,能送一个足够高的电压回来;结果,因为衰减,接点闭合了,但是电压不够高,DI认为是0信号。适当的提升DI的查询电压,可以解决长线路时的信号衰减问题。这也是经过了多年的总结和实验,发现48V DC是很合适的。线路敷设1km,还可以保证能检测到信号。
The problem of signal attenuation still exists in the di signal circuit of 24 V DC. Now the concept of centralized control room is popular, and tens of thousands of cables are connected to the centralized control room. Mutual interference is very serious. The laying distance of the cable is virtually longer. The longer the cable is, the easier it is to attenuate, because the line resistance will increase a lot. In theory, a 24 V DC line can support a distance of 500 meters, but in fact, the field problems are quite complex. Many times, when the cable is laid for 300 meters or 400 meters, the voltage has been attenuated obviously. In addition, if the index of the cable itself is not enough, the attenuation will be more serious. The result is that the original signal is closed, and a high enough voltage can be sent back; as a result, because of attenuation, the contact is closed, but the voltage is not high enough, and di thinks it is a 0 signal. Properly increasing the inquiry voltage of DI can solve the problem of signal attenuation in long line. After many years of summary and experiments, it is found that 48V DC is very suitable. When the line is laid for 1km, the signal can be detected.
综上所述,DCS控制系统DI卡件选择48V DC做为回路电压是有它优于24V DC的地方,同时这就需要与DI相关的设备支持48V DC。希望以上内容对大家有所帮助,如想了解更多内容请点击我们的网站:浙大中控电源http://www.sdjkyqyb.com
To sum up, the DCS control system Di card chooses 48V DC as the loop voltage, which is better than 24V DC. At the same time, it needs the equipment related to Di to support 48V DC. I hope the above content is helpful to you. If you want to know more, please click our website: Zhejiang University central control power http://www.sdjkyqyb.com
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