AAT141-S00輸入模塊
AAR181-SE0/R8S10 AAI141-SE0/A4S10 AAV141-SE0/A4S10 AAV142-SE0/A4S10 AAV542-SE0/A4S10
AAR181-SF0/R8S10 AAI141-SF0/A4S10 AAV141-SF0/A4S10 AAV142-SF0/A4S10 AAV542-SF0/A4S10
AAR181-H00/R8S10 AAI141-H00/A4S10 AAV141-H00/A4S10 AAV142-H00/A4S10 AAV542-H00/A4S10
AAR181-H50/R8S10 AAI141-H50/A4S10 AAV141-H50/A4S10 AAV142-H50/A4S10 AAV542-H50/A4S10
TC Input/RTD Input Modules (Isolated)
These modules receive signals from mV, thermocouple (TC) and RTD. They can be used in dual redundant con?guration.
Items | Speci?cations | ||
Model | AAT141 | AAR181 | |
Number of input channels | 16, isolated (*7) | 12, isolated | |
Input signal | TC: JIS C1602:1995, IEC584:1995 Type J, K, E, B(*1), R, S, T, N mV: -100 to 150 mV, -20 to 80 mV |
RTD: JIS C1604:1997, IEC751:1995 Pt100 (3-wire type)(*6) | |
Switching input signals | TC/mV can be set individually for CH1 to CH16. | CH1 to CH12 are RTD inputs. | |
Allowable input voltage | ±5 V | ±5 V | |
Withstanding voltage | Between input and system: 1500 V AC, For 1 minute | ||
Input resistance | Power ON | 2 MΩ or more | |
Power OFF | 2 MΩ or more | ||
Accuracy | TC: ±30 µV MV: ±80 µV for span (-100 to 150 mV) ±30 µV for span (-20 to 80 mV) |
RTD: ±120 mΩ | |
Allowable total resistance of signal source plus wiring |
1000 Ω or less |
40 Ω or less (wiring resistance per wire) (*2) | |
Effect of allowable signal source resistance (1000 Ω) |
±20 µV(*3) |
— | |
Reference junction compensation accuracy |
Within ±1 °C (*4) (*5) |
— | |
Measurement current | — | RTD: 1 mA | |
Temperature drift | ±80 µV/10 °C (-100 to 150 mV input) ±30 µV/10 °C (TC/-20 to 80 mV input) |
±120 mΩ/10 °C (RTD input) | |
Data update period | 1 s | ||
Burn-out | All channels can be set together. Setting: Not available/available (UP/DOWN) detection time: 60 s | ||
Maximum current consumption | 450 mA (5 V DC) | 450 mA (5 V DC) | |
Weight | 0.2 kg | ||
External connection | Pressure clamp terminal |
Voltage Output Modules (Isolated)
It can be used in dual redundant con?guration.
Items | Speci?cations |
Model | AAV544 |
Number of output channels | 16, isolated |
Output signal | -10 to 10 V |
Withstanding voltage | Between output and system: 1500 V AC Withstanding voltage, For 1 minute (*1) |
Allowable load resistance | 5 kΩ or more |
Accuracy | The larger one among ±12 mV or ±0.3 %FS |
Data update period | 10 ms |
Drift due to ambient temperature change | The larger one among ±0.1 %/10 ?C or ±10 mV/10 ?C |
Maximum current consumption | 860 mA (5 V DC) |
Weight | 0.2 kg |
External communication | Pressure clamp terminal, MIL connector cable, Dedicated cable (KS1) |
*1: The withstanding voltage for using the dedicated cable is 500 V AC (between the input signal and the system).
The withstanding voltage for using MIL connector cable depends on the electrical speci?cations of its cable.
3 人為故障
在對DCS系統進行維護或故障處理時,有時會發生人為誤操作現象,這對于經常進行系統維護或新參加系統檢修維護的人員來說都是會發生的。一般在修改控制邏輯、下裝軟件、重啟設備或強制設備、保護信號時zui易發生誤操作事件。AAT141-S00輕則導致部分測點、設備異常,重則造成機組或主要輔機設備停運,后果是非常嚴重的。在使用DCS的電廠、石化、化工廠,人為誤操作發生的故障在熱工專業中的不安全事件中占有很大比例。
4 電源故障
電源方面的問題也較多,如備用電源不能自投,保險配置不合理及DPU電源內部故障等造成電源中斷,穩壓電源波動引起保護誤動及接插頭接觸不良導致穩壓電源無輸出;有的系統整個機柜通過一路保險供所有輸入信號或一路電源外接負載很大,還有的控制電源既未接UPS又未有冗余備用。
5 SOE工作不正常
SOE的結論對事故的分析、判斷起了很重要的作用,但在現實中,許多電廠發生保護動作等情況時SOE未記錄下來或記錄時間與實際情況不符。如××電廠#1機組出現過SOE事件順序追憶時間與實際跳閘時間不相對應,SOE時間打印瀏覽后不能返回,*跳閘原因在事件順序中不能*個反映,SOE時間順序數據不能設置等問題。而有的電廠在幾次事故分析時發現SOE結論中的時序與歷史曲線中的時序有偏差,有時甚至時序顛倒,具體表現于同一點在歷史曲線和SOE中發生時間不*,且有時偏差很大,這會延誤事故分析的進程,有時甚至誤導事故分析方向。SOE問題既與系統設計不合理,SOE點沒*集中在一個DPU上有關,也與系統硬件及軟件設計考慮不周有關。
6 干擾造成的故障
干擾造成DCS故障的事例也不少。D璐系統的干擾信號可能來自于系統本身,也可能來自于外部環境。
由于不同的DCS系統對接地都有嚴格的規定,一旦接地電阻或接地方式達不到要求,就會使網絡通信的效率降低或增加誤碼的可能,輕則造成部分功能不正常,重則導致網絡癱瘓。
電源質量同樣影響系統的穩定運行。用于DCS系統的電源既要保證電壓的穩定,也要保證在一路電源故障時,無擾切換至另一路電源,否則會對系統工作產生干擾。
過程控制處理機主/備處理機之間的切換有時也會導致干擾。
另外,大功率的無線電通信設備如手機、對講機等在工作時,極易造成干擾,危及系統運行。