GB67456
GB67456
【詢價`1 8 0 5 0 0 3 6 9 4 6 `】【詢價-- 】【詢價 :1811245942】
3、 硬件濾波及軟件抗如果措施
由于電磁干擾的復(fù)雜性,要根本消除迎接干擾影響是不可能的,因此在PLC控制系統(tǒng)的軟件設(shè)計和組態(tài)時,還應(yīng)在軟件方面進(jìn)行抗干擾處理,進(jìn)一步提高系統(tǒng)的可靠性。常用的一些措施:數(shù)字濾波和工頻整形采樣,可有效消除周期性干擾;定時校正參考點電位,并采用動態(tài)零點,可有效防止電位漂移;采用信息冗余技術(shù),設(shè)計相應(yīng)的軟件標(biāo)志位;采用間接跳轉(zhuǎn),設(shè)置軟件陷阱等提高軟件結(jié)構(gòu)可靠性。
信號在接入計算機(jī)前,在信號線與地間并接電容,以減少共模干擾;在信號兩極間加裝濾波器可減少差模干擾。
對干較低信噪比的模擬量信號.常因現(xiàn)場瞬時干擾而產(chǎn)生較大波動,若僅用瞬時采樣植進(jìn)行控制計算會產(chǎn)生較大誤差,為此可采用數(shù)字濾波方法。
現(xiàn)場模擬量信號經(jīng)A/D轉(zhuǎn)換后變成離散的數(shù)字信號,然后將形成的數(shù)據(jù)按時間序列存入PLC內(nèi)存。再利用數(shù)字濾波程序?qū)ζ溥M(jìn)行處理,濾去噪聲部分獲得單純信號, 可對輸入信號用m次采樣值的平均值來代替當(dāng)前值,但井不是通常的每采樣。次求一次平均值,而是每采樣一次就與zui近的m-l次歷史采樣值相加,此方法反應(yīng)速度快,具有很好的實時性,輸入信號經(jīng)過處理后用干信號顯示或回路調(diào)節(jié),有效地抑制了噪聲干擾。
由干工業(yè)環(huán)境惡劣,干擾信號較多, I/ O信號傳送距離較長,常常會使傳送的信號有誤。為提高系統(tǒng)運行的可靠性,使PLC在信號出錯倩況下能及時發(fā)現(xiàn)錯誤,并能排除錯誤的影響繼續(xù)工作,在程序編制中可采用軟件容錯技術(shù)。
VICTAULIC 5" GROOVED TEE PIPE FITTING NO. 20
UNKNOWN MFG * 1 " BALL VALVE * CFF SS-3
DELVAL 175PSI, 6" BUTTERFLY VALVE 5006141B1B0 DN150/6"
SMC 110VAC 14-145 PSI SOLONOID VALVE W/ BASE, VPN-8-FG-D *NEW*
VICKERS 500PSI OIL COOLER OCW-S-3-F-30
NUMATICS 110/120V .05A 14.5-120 PSIG 3/8" NPT SOLENOID VALVE, 92178-2AC
CASH ACME 1-1/2"NPT, 30PSI PRESSURE REDUCING VALVE G-60
MILWAUKEE 1/4" 300SWP 1000WOG GATE VALVE
JAMESBURY 6" CF8M VALVE 5152W-31-3600TS?-2 ACTUATOR ST-400 B W/ PMV P-2000
GEMINI VALVE, 1/2" NPT, 1000PSI CWP, PNEUMATIC VALVE & ACTUATOR, B412 / 89 6RTV6
RP&C 1/2" GATE VALVE 800 A105N
PARKER/SHRADER BELLOWS 200PSI, SELECTOR VALVE N1643003 *NEW*
MAC 1/8"NPT, 35-150PSI, PNEUMATIC SIGNAL PRESS VALVE 16001-111-111
WATTS 1-1/4", 200PSI, 10-35RANGE, LOW PRESSURE REGULATOR VALVE U5 B LP, 8214C *N
ASCO RED-HAT 110/120V 6.1/8.1W 50/60HZ 3/8" NPT SOLENOID VALVE, 8316G54 *NEW*
AQUATROL 1/2"NPT, 125PSI, VALVE 132
RP&C 1/2" GATE VALVE 800 A105N
PARKER/SHRADER BELLOWS 200PSI, SELECTOR VALVE N1643003 *NEW*
MAC 1/8"NPT, 35-150PSI, PNEUMATIC SIGNAL PRESS VALVE 16001-111-111
WATTS 1-1/4", 200PSI, 10-35RANGE, LOW PRESSURE REGULATOR VALVE U5 B LP, 8214C *N
ASCO RED-HAT 110/120V 6.1/8.1W 50/60HZ 3/8" NPT SOLENOID VALVE, 8316G54 *NEW*
AQUATROL 1/2"NPT, 125PSI, VALVE 132
NUMATICS 10BAR, 14.5-145PSIG PNEUMATIC VALVE L23JJ4520 *NEW,SEALED*
ASCO RED-HAT 110/120V 50/60HZ SOLENOID VALVE COIL, 238610-032D *NEW*
ROEMHELD CHECK VALVE CLR-2954-429-V / 2954429 *NEW*
SMC 1/4" NPT 15-150 PSI SHUT OFF VALVE, NVHS2000
BETTIS 120PSI ACTUATOR 106581 / RPB1000-SR4(CW)