1756－L62S

1756－L62S

1756－L62S 输入电路是PLC接受开关量、模拟量等输入信号的端口，其元器件质量的优劣、接线方式及是否牢靠也是影响控制系统可靠性的重要因素。以开关量输入为例，按钮、行程开关的触点接触要保持在良好状态，接线要牢固可靠。机械限位开关是容易产生故障的元件，设计时，应尽量选用可靠性高的接近开关代替机械限位开关。此外，按钮触点的选择也影响到系统的可靠性。在设计电路时，应尽量选用可靠性高的元器件，对于模拟量输入信号来说，常用的有4～20mA、0～20mA直流电流信号；0～5V、0～10V直流电压信号，电源为直流24V. 　　对于开关量输出来说，PLC的输出有继电器输出、晶闸管输出、晶体管输出三种形式，具体选择哪种形式的输出应根据负载要求来决定，选择不当会使系统可靠性降低，严重时导致系统不能正常工作。如晶闸管输出只能用于交流负载，晶体管输出只能用于直流负载。此外，PLC的输出端子带负载能力是有限的，如果*过了规定的较大限值，必须外接继电器或接触器，才能正常工作。外接继电器、接触器、电磁阀等执行元件的质量，是影响系统可靠性的重要因素。常见的故障有线圈短路、机械故障造成触点不动或接触不良。这一方面可以通过选用高质量的元器件来提高可靠性，另一方面，在对系统可靠性及智能化要求较高的场合，可以根据电路中电流异常的情况对输出单元的一些**部位进行诊断，当检测到异常信号时，系统按程序自动转入故障处理，从而提高系统工作的可靠性。若PLC输出端子接有感性元件，则应采取相应的保护措施，以保护PLC的输出触点。 Hewlett Packard 489363-001 Hp Viola-gl8e Mini-atx System Board A4856-69101 Hewlett-Packar?d Superdome PCI Card Cage Hewlett Packard Agilent Multimeter 3468B Four Wire Type 3468 HEWLETT PACKARD 27289B HP 27289-69040 ADVANCESTACK ROUTER 240 HEWLETT PACKARD 0950-3033 HP 2.6GB, 4X optical disk dri HEWLETT PACKARD 00288-001 HP3M BACK**NE MODULE HEWLETT PACKARD 2728** HP ADVANCESTACK ROUTER 440 HEWLETT PACKARD 901-21300-00 HP3M BACK**NE MODULE HEWLETT PACKARD A1809-60006 HP9000 PB BUS CONVERTER MOD HEWLETT PACKARD A1703-80031 HP 9000 MEMORY CARRIER MODU HEWLETT PACKARD C1160-85302 HP VERTICAL MOTION MOTOR HEWLETT PACKARD A4200-00021 DISK TRAY BOTTOM HEWLETT PACKARD C2986-61001 HP 6GB 2.5' SLIM HARD DRIVE HEWLETT PACKARD C1160-66501 HP OPTICAL JUKEBOX MODULE HEWLETT PACKARD C2986-60101 HP 6GB 2.5' SLIM HARD DRIVE HEWLETT PACKARD C1534-66001 2GB 4MM 5.25' MOUNT-TRAY DA HEWLETT PACKARD C1561A / C1561-60003 SURESTORE 12000E TAPE DRIVE HEWLETT PACKARD C1113-69100 HP 2.6GB, 4X optical disk d HEWLETT PACKARD C1113-60100 HP 2.6GB, 4X optical disk HEWLETT PACKARD C1552-69203 HP SURESTORE DAT8 TAPE DRIV HEWLETT PACKARD CA31214-C016FJ HP D640 3.5' FLOPPY DISK HEWLETT PACKARD C7200-66503 HP SURESTORE MAIN PC BOARD HEWLETT PACKARD J4119A HP PROCURVE POWER SUPPLY HEWLETT PACKARD F2072-69017 HP OMNIBOOK 6000 14' LCD DI HEWLETT PACKARD RG5-3945-000 HP LJ 8550 MODULE HEWLETT PACKARD RG5-5142-000 LJ4500 DRUM DRAWER ASSY HEWLETT PACKARD J2092A J2092-60001 HP-PB 16 PORT RS232 MUX MODULE HEWLETT PACKARD J3191-69101 HP ADVANCESTACK EXPANSION M HEWLETT PACKARD J3191-61101 HP ADVANCESTACK EXPANSION M Hewlett Packard Photosmart eStation e-All-in-One Printer (CQ140A#B1H) 885631240359, New, USA Warranty, Authorized HP Dealer Hewlett Packard HP 54504A Digitizing Oscilloscope Hewlett Packard HP 54510A Digitizing Oscilloscope Hewlett Packard 2671G Dot Matrix Line Printer For Parts Hewlett Packard X752C Directional Coupler WR90 HP Hewlett Packard LaserJet 4200 Toner Cartridge Black Q1338A HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M1722A CODEMASTER XL+ DEFIBRILLATO HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M1722B CODEMASTER XL+ DEFIBRILLATO HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M3000A VERIDIA PATIENT MONITOR 5 L HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M3046A VERIDIA PATIENT MONITOR 5 L HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M437** VERIDIA PATIENT MONITOR 5 L HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M5500B DEFIBRILLATOR 12 PIN 5 LW S HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M3500B DEFIBRILLATOR 12 PIN 5 LW S HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M3500B DEFIBRILLATOR 8 PIN 5 LW SE HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M2601A TELEMETRY TRANSMITTER 5 LW HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL M5500B DEFIBRILLATOR 8 PIN 5 LW SE HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL 862474 - C3 BEDSIDE MONITOR 5 LW S HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL 862475 - C3 BEDSIDE MONITOR 5 LW S HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL 862478 - C3 BEDSIDE MONITOR 5 LW S HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL 862479 - C3 BEDSIDE MONITOR 5 LW S HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL 78352C ECG MONITOR 12 PIN 5 LW SET HEWLETT PACKARD/AGILEN?T/ZYMED/PHILIP?S MEDICAL 78352A ECG MONITOR 8 PIN 5 LW SET