IC670MDL742
IC670MDL742
IC670MDL742
IC670MDL742
那么它的RS-485总线输出将会处于发送状态，占用了通讯总线，
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《邮@.com》这时其他的分机就无法与主机进行通讯。如果某个分机出现异常情况下（如死机），就会一直占用总线，导致整个系统通讯崩溃。因此在电路设计时，要保证系统上电复位时75176的DE端电位为“0”，采用如图2的接法。由于MSP430在复位期间，I/0口电位为“1”，发光管不发光，光电三极管不导通，75176的DE端电位为“0”，释放总线，从而有效地解决复位期间分机“咬”总线的问题。增强了系统通讯的可靠性和稳定性，同时有效地解决了工，作现场与控制室之间的分离，保证了工作人员人身安全。
图2 RS-485接口原理图
2.4 单片机控制的M.DBUS通讯原理
目前，工业上的MODBUS通讯协议已经成为电子控制器上的一种通用语言协议。通过此协议，控制器相互之间、控制器经由网络（例如以太网）和其它设备之间可以通讯。它已经成为一通用工业标准。用它来实现不同厂商生产的控制设备连成工业网络，进行集中监控。
基于此，可以根据实际工业网络数据采集的一主多从的实际数据选择模型，该模块采用了此协议，因为协议定义了一个控制器能认识使用的消息结构，而不管它们是经过何种网络进行通讯的。因此不管上位机是什么样类型的测控设备，就按固定的MODBUS通讯协议要求的协议格式来回应来自主设备的请求，并进行侦测错误记录。按照协议中要求的消息域格局和内容的公共格式回应。
Woodward 5464-768 CPU - DCS II
Woodward 5464-827 CPU MODULE
Woodward 5464-828
Woodward 5464-829
Woodward 5464-830 A/I 4-20
Woodward 5464-833 4 ch
Woodward 5464-834
Woodward 5464-836 REMOTE XCVR
Woodward 5464-843 NetCon CPU Card
Woodward 5466-006 4-20mA Input
Woodward 5466-017 2 CH ACTUATOR DRIVER
Woodward 5466-026 DUPLEX CUR IN
Woodward 5466-031 Netcon I/O Controller?????
Woodward 5466-032 FTIO MODULE
Woodward 5466-033 CPU Module
Woodward 5466-041 2C Pos Control
Woodward 5466-042 CPU (GAP Compatible) - DCS
Woodward 5466-061 Module Master CPU
Woodward 5466-063 NetCon CPU Card
Woodward 5466-074 CPU Mod
Woodward 5466-250 netcon B FTIO
Woodward 5466-253 MPU A I/O
Woodward 5466-258 NetCon/MicroNet Discreet I/O Card 24/12
Woodward 5466-268
Woodward 5466-272 Solnd Mon
Woodward 5466-274 FTIO
Woodward 5466-315 NetCon/MicroNet Analog I/O Card
Woodward 5466-316 MPU A I/O
Woodward 5466-332 ANALOG I/O 24/8
Woodward 5466-336 SIO
Woodward 5466-340 Netcon F/O XCVR
Woodward 5466-348 Netcon 5000B SIO
Woodward 5466-351 Netcon CPU 040 with LLC Memory
Woodward 5466-352 CPU Module
Woodward 5466-353 MAIN XCVR
Woodward 5466-355 REMOTE XCVR
Woodward 5466-409 NetCon/MicroNet CPU Card
Woodward 5466-411 Ethernet Module (RJ45)
Woodward 5466-419 NT CPU
Woodward 5466-425 24/8A I/O
Woodward 5466-458
Woodward 5500-018
Woodward 5500-134 Ext. Card
Woodward 5500-159C 505 Relay Board
Woodward 5500-510
Woodward 5500-559 Buffer Board
Woodward 5500-563
Woodward 5501-003 Circuit Board for Peak 150
Woodward 5501-340
Woodward 5501-341
Woodward 5501-367 FTM (Field Termination)
Woodward 5501-376 FTM, ANALOG, HI DENS
Woodward 5501-411
Woodward 5501-428 2 CH ACTUATOR DRIVER
Woodward 5501-432 2 CH ACTUATOR DRIVER
Woodward 5501-465
Woodward 5501-466 MicroNet Power Supply
Woodward 5501-469 CPU LM6000 PC & PA
Woodward 5501-470 CPU_040 W/O LL?Memory??
Woodward 5501-471 NetCon/MicroNet SIO Card
Woodward 5501-510 FT Relay
Woodward 5503-173 MicroNet VME CPU Adapter
Woodward 5503-279 TC/RTD
Woodward 5503-282 FTM, analog
Woodward 5503-335 CPU
Woodward 6945-377 3103 Gas Fuel Valve
Woodward 8200-015 Peak 150 (HVAC - No ModBus)
Woodward 8200-019 PEAK 150
Woodward 8200-177 DRIVER, EM DIGITAL/ANALOG
Woodward 8200-203 ProTech 203
Woodward 8200-226 SPC (servo position controller)
Woodward 8200-314 GS/L Driver
Woodward 8220-805 Final Driver
Woodward 8226-043 OCP (operator control panel)
Woodward 8230-568 Control Panel
Woodward 8230-805 FINAL DRVR
Woodward 8230-815 HP Final Drive
Woodward 8230-827 LP Final Driver
Woodward 8230-840
Woodward 8230-841
Woodward 8230-896 Final Driver - Water
Woodward 8230-898 FINAL DRVR
Woodward 8234-167O 501 Chassie
Woodward 8234-213 Chassis - NetCon A
Woodward 8234-346A 501 Chassie
Woodward 8236-026
Woodward 8236-027 Operate Control Panel
Woodward 8236-039 OCP (operator control panel)
Woodward 8236-039 OCP (operator control panel)
Woodward 8236-043 Interface 43027
Woodward 8236-144 Light Panel
Woodward 8236-144D Light Panel
Woodward 8238-002 505E Bulkhead
Woodward 8238-007 505 Bulkhead
Woodward 8238-008 505 Flush Mount
Woodward 8238-009 505E Bulkhead
Woodward 8239-001 DSM Synchronizer
Woodward 8239-002 DSM Synchronizer
Woodward 8239-005 DRFD
Woodward 8239-006 Digital Remote Final Driver
Woodward 8239-007 Digital Remote Final Driver
Woodward 8239-008 Digital Remote Final Driver
Woodward 8239-015 Digital Remote Final Driver
Woodward 8239-016 DRFD CONTROL ASSEMBLY
Woodward 8239-939
Woodward 8240-084 EGB10C governor
Woodward 8250-022 remote servo
Woodward 8250-226 EG10P p/n A8250-226
Woodward 8250-421 EG3P oil motor
Woodward 8250-501 actuator
Woodward 8250-570
Woodward 8250-807 TA-20 Actuator
Woodward 8250-818 Governor
Woodward 8256-021 EPG Actuator
Woodward 8270-092 EG-A Control Box
Woodward 8270-122 2301 Power Supply, p/n
Woodward 8270-201
Woodward 8270-741 MOTOR OPERATED POTENTIOMETER
Woodward 8270-758 2301 SIGNAL CONVERTER
Woodward 8270-768 2301 AMPLIFIER
Woodward 8271-147 Load Sensor
Woodward 8271-467 2301 Load Share and Speed Control
Woodward 8271-472 2301 Load Sharing & Speed Control
Woodward 8271-652 2301 Load Share and Speed Control
Woodward 8271-674 Power Supplies
Woodward 8271-872 Import/Export Control
Woodward 8272-385 SPM Synchronizer
Woodward 8272-394 Real Power Sensor
Woodward 8272-447 Motor Operated Pot
Woodward 8272-464
Woodward 8272-684
Woodward 8272-684
Woodward 8272-695 Real Power Sensor
Woodward 8272-720 Real Power Sensor
Woodward 8272-781A Real Power Sensor
Woodward 8273-041 ATLAS SC
Woodward 8273-276 377A7823P001,Atlas PC 2x4 Sc w/act,LV
Woodward 8280-071 Hydraulic Pump
Woodward 8280-415 Digital Speed Control
Woodward 8280-505 723 Plus
Woodward 8290-195 Flo-Tech Speed Control
Woodward 8291-020 EHPC
Woodward 8301-633 MicroNet
Woodward 8405-020
Woodward 8406-113 EGCP-3 DIGITAL CONTROL
Woodward 8406-121 EGCP-2
Woodward 8434-246 Main Chassises w/ LED & P.B
Woodward 8512-135
Woodward 8516-038
Woodward 8516-039 TG 13
Woodward 8516-042 4000 RPM CCW
Woodward 8516-051 TG-13E, 4000 RPM, CCW MS CONN
Woodward 8516-068 TG-13E Actuator, Pressure Drive
Woodward 8516-076 TG-13A
Woodward 8570-412 PG Dial Governor, p/n C8570-412
Woodward 8575-241
Woodward 8575-377
Woodward 8580-064 Tachometer CIT Sensor
Woodward 8580-069 On Engine Gearbox Hydraulic Pump for Metering Valves
Woodward 8580-071 Engine Gearbox Hydraulic Pump
Woodward 8580-085 Engine Gearbox Hydraulic Pump
Woodward 8580-086 Hydraulic Pump
Woodward 8900-067 Sensor
Woodward 8901-457 CPC
Woodward 8901-881 Fuel/Water Valve
Woodward 8904-289 Valve
Woodward 8904-484 Gas Shutoff Valve with Suppression
Woodward 8904-773 Control 8904-88
Woodward 8915-004 1907 Liquid valve with TM-55 Actuator
Woodward 8915-005 3103 Gas Valve with TM-55 Actuator
Woodward 8915-011 Control Valve-TM55P/3103 Low Temp Gas Fuel
Woodward 8915-024 Liquid Fuel Valve
Woodward 8915-046 Control Valve-TM55P/1907 Liq
Woodward 8915-075 Control Valve-TM40LP/3151A Water
Woodward 8915-094 Control Valve-TM55P/3103 High Temp Gas Fuel
Woodward 8915-103 Control Valve-TM40/Liquid LP
Woodward 8915-111
Woodward 8915-1146 3103/EM35 GAS VALVE
Woodward 8915-118
Woodward 8915-123 Control Valve-Gas Fuel TM55P/3103 Hi Temp 1" Port
Woodward 8915-385 Control Fuel TM55P