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浙大中控dcs卡件XP313:DCS系统无法操作调节阀怎么办?

2021-01-11 16:58:49 来源:http://www.sdjkyqyb.com/ 53

故障现象
Fault phenomenon
PIC708从DCS操作站上无法控制调节阀。操作界面显示该点为“初始化”状态。
Pic708 can not control the control valve from DCS operation station. The operation interface shows that the point is in "initialization" state.
故障分析
fault analysis 
出现此现象,一般为DCS输出回路开路所致。如定位器损坏,接线松动,断电、安全栅损坏等均能引起此故障。由于现场环境恶劣,震动较大,首先考虑是否为定位器接线松动所致。
This phenomenon is generally caused by open circuit of DCS output circuit. If the positioner is damaged, the wiring is loose, the power is cut off, and the safety barrier is damaged, the fault can be caused. Because of the bad environment and large vibration, the first consideration is whether it is caused by the loose wiring of the positioner.
处理过程
Treatment process
1.办理好在线检修作业票后,到现场检查,发现定位器接线无松动。测量定位器工作电压为4.95V,该定位器为FISHER公司DVC6010型智能定位器,工作电压应该在10V左右。断开定位器的接线,测开路电压为17.5V,正常。再测其短路电流(因该定位器为有源隔离栅供电,所以现场短路测量不会影响其本安特性),只有0.78mA,正常值应大于20mA。看来供电不正常。为确定是单纯供电问题,还是因为定位器损坏造成的供电异常,用一台信号发生器给定位器加入电流信号,调节阀工作正常。由此可以断定故障出在定位器之前。
1. After handling the online maintenance work order, the on-site inspection found that the locator wiring was not loose. The working voltage of the positioner is 4.95v. The positioner is Fisher dvc6010 intelligent positioner, and the working voltage should be about 10V. Disconnect the wiring of the positioner and measure the open circuit voltage to be 17.5V, which is normal. The short-circuit current is only 0.78ma, and the normal value should be greater than 20mA. It seems that the power supply is abnormal. In order to determine whether it is the simple power supply problem or the abnormal power supply caused by the damage of the positioner, a signal generator is used to add the current signal to the positioner, and the regulating valve works normally. It can be concluded that the fault is before the positioner.
                       浙大中控dcs卡件XP313
2.检查定位器至中间接线箱至机房的电缆,线路电阻均正常。由此,故障缩小到DCS输出卡件到机房端子排之间。
2. Check the cable from the positioner to the middle junction box to the machine room, and the line resistance is normal. Thus, the fault is reduced to between the DCS output card and the computer room terminal block.
短接DCS输出卡端子,DCS界面的故障消失,排除卡件故障。在短接安全栅的输出侧,故障不消失,将此处端子松开后重新压紧,短接故障可以消失,但不短接,故障仍然存在,说明故障不止一处。短接安全栅的输出侧,故障没有消失。但是这一侧直接连接现场的定位器,从这一侧到定位器之间的线路已经测试过,没有问题。会不会是安全栅性能变劣,带载能力下降所致呢?
If the terminal of DCS output card is short circuited, the fault of DCS interface disappears and the card fault is eliminated. In the output side of the short circuit barrier, the fault does not disappear. If the terminal is loosened and pressed again, the short circuit fault can disappear, but if it is not short circuited, the fault still exists, indicating that there is more than one fault. Short circuit the output side of the safety barrier, and the fault does not disappear. But this side is directly connected to the field positioner, and the circuit from this side to the positioner has been tested, and there is no problem. Can it be caused by the deterioration of barrier performance and load carrying capacity?
3.将安全栅输出侧接线断开,在此处接入一个250欧姆的负载电阻,此时故障消失,电压为1V,电流为4mA,将250欧姆的负载电阻拆下,将接线复原,仪表故障消失,定位器电压为9.6V。由此可以看出,安全栅的输出侧也存在接触不良的情况,当断开又重新压紧后,故障排除了。
3. Disconnect the wiring at the output side of the safety barrier and connect a 250 ohm load resistor here. At this time, the fault disappears. The voltage is 1V and the current is 4mA. Remove the 250 ohm load resistor and restore the wiring. The instrument fault disappears and the locator voltage is 9.6V. It can be seen that the output side of the safety barrier also has poor contact. When it is disconnected and pressed again, the fault is eliminated.
结语,本例中,故障是因为安全栅的输入端同时存在接触不良的情况所致。由于接线均压有针型接线端子,上紧后,经过一段时间,由于金属材料的形变及氧化,使得接头出现松动及接触电阻变大的现象,从而引起仪表的故障。查明原因后,利用装置停车消缺的时机,将机房内所有接线端子紧固一遍,查出多处线头松动的问题,及时消除了隐患。
Conclusion: in this case, the fault is caused by poor contact at the input end of the safety barrier. Because there are needle terminals in the wiring, after a period of time, due to the deformation and oxidation of metal materials, the joints become loose and the contact resistance becomes larger, resulting in the failure of the instrument. After finding out the causes, the device was used to stop and eliminate the defects, and all the wiring terminals in the machine room were fastened once. The problems of loose wire ends in many places were found out, and the hidden dangers were eliminated in time.
建议,装置在检修期间,应当检查控制系统接线柜、中间接线箱和现场仪表接线,并且进行清灰和紧固端子工作,尤其是振动比较大的区域。
It is suggested that the wiring of control system wiring cabinet, intermediate wiring box and field instrument should be checked during the maintenance of the device, and the dust cleaning and terminal fastening should be carried out, especially in the area with large vibration.
以上是浙大中控dcs卡件XP313对DCS无法操作调节阀的原因介绍,希望对大家有所帮助,如想了解更多精彩资讯请点击我们的网站:http://www.sdjkyqyb.com
The above is the reason why the DCS card xp313 of Zhejiang University central control can not operate the control valve. I hope it can help you. For more wonderful information, please click our website: http://www.sdjkyqyb.com
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