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I-O Display Systems Basic I/O Product manual Installation, RS-485 Programming, 2-5Vol.2

Models: Basic I/O Product

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Installation 2

RS-485 Programming:

The BASIC I/O AD will work equally well when connected as RS-422 or RS-485. However special host programming considerations may be necessary when implementing an RS-485 network. Unlike RS-422 where both the transmit and Receive signals have their own differential pair of conductors, RS-485 utilizes only one differential pair. The single pair of conductors is used bidirectionally and handles both transmit and receive signals. In order for this to be possible, the transmitter for each device on this type of network must be enabled and disabled whenever a message is to be sent. The transmitter for the BASIC I/O AD is designed to handle this control automatically, the transmitter control for most popular RS-485 cards that are installed in the Host computer must be controlled by the user program. This control is not straight forward and may impact the overall system throughput with inherent delay periods. The following is a typical instruction/ response transaction between a host computer and a BASIC I/O AD using RS-485.

1)The Host computer enables its RS-485 transmitter (usually via the RTS line)

2)The Host then sends an instruction to the BASIC I/O AD in the form of an ASCII printable string.

3)Once the Host determines that the string has been completely sent, the RS-485 transmitter is disabled.

4)Every BASIC I/O AD on the network receives the instruction and begin to decode it. That particular BASIC I/O AD addressed begins to construct a response.

5)Once the carriage return is of the instruction is received, then begins to transmit a response.

6)The Host receives the response and takes the appropriate action.

2-5(Vol.2)

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I-O Display Systems Basic I/O Product manual Installation, RS-485 Programming, 2-5Vol.2

Contents

Page Basic I/O Product Family Page Vol.1 Table of ContentsCommunication verification . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 Table of ContentsTHE BASIC I/O The Basic I/OAnalog input instruction types are The Basic I/OANALOG INPUTS ANALOG OUTPUTS The Basic I/ODIGITAL INPUTS The Basic I/ODIGITAL OUTPUTS The Basic I/OSYSTEM THROUGHPUT The Basic I/ODigital Input Data Digital M Time for 1-16 channels The Basic I/O1-8Vol.1 The Basic I/OCOMMUNICATION PROTOCOL ANALOG OUTPUTS, 12 BIT The Basic I/OAvailable I/O Modules ANALOG INPUTS, 12 BITThe Basic I/O DIAGNOSTICSPHYSICAL CHARACTERISTICS 1-11Vol.1 The Basic I/OPRODUCT TEST BASIC I/O Models1-12Vol.1 The Basic I/OFIGURE 2-1 BASIC I/O FOOTPRINT Setup & InstallationMOUNTING POWER WIRING Setup & Installation2-3Vol.1 Setup & InstallationCOMMUNICATING WITH THE BASIC I/O Repeat Setup & InstallationFigure 2-3 Multidrop V.S. Repeat networks Multidrop RS-485 can only be multidropRS-485 Setup & InstallationRS-422 RS-485 Programming Setup & Installation2-7Vol.1 Setup & InstallationCOMMUNICATION WIRING R35 is the 1.5k from prior - bias resistor Setup & InstallationNetwork load V.S. Noise suppression R34 is the 1.5k from prior +bias resistor2-9Vol.1 Setup & InstallationRS-422 HOST TO BASIC I/O Figure 2-5 RS-422 Host to BASIC I/O wiring 2-10Vol.1 Setup & InstallationBASIC I/O TO BASIC I/O RS-422 MULTIDROP OR REPEATER Figure 2-6 RS-422 BASIC I/O-To-BASIC I/O multidrop2-11Vol.1 Setup & InstallationRS-485 Host to BASIC I/O Figure 2-7 RS-485 To-BASIC I/O 2-12Vol.1 Setup & InstallationBASIC I/O to BASIC I/O RS-485 Multidrop only Figure 2-8 RS-485 BASIC I/O to BASIC I/O MultidropFigure 2-9 BASIC I/O Connectors, Switches and Indicators Setup & InstallationBASIC I/O setup Baud Rates Setup & InstallationAnalog/ Digital Addresses2-15Vol.1 Setup & InstallationProtocol Handshake Types L2 Multidrop Setup & InstallationNetwork Type Switch L1 RepeaterThe underlined values represent setup parameters that can be changed Setup & InstallationSetup via Pushbutton The underlined values represent setup parameters that can be changedCommunication verification Setup & InstallationOther error codes Setup & InstallationHardware error codes Error CodeAnalog Inputs Setup & InstallationFigure 2-10 AC Current and Voltage Wiring 2-21Vol.1 Setup & InstallationFigure 2-11 Analog Voltage and Current input Wiring Figure 2-12 Temperature Input WiringNote Analog modules run hot to the touch Setup & InstallationFigure 2-13 Analog Voltage and Current Output Wiring Analog outputs2-23Vol.1 Setup & InstallationFigure 2-14 Digital Input Wiring Digital Inputs2-24Vol.1 Setup & InstallationFigure 2-15 Digital Output Wiring Digital OutputsCOMMUNICATION PROTOCOL IndexVol.1 Page Nov. 24 BASIC I/O ADTable of Contents RS-485 Host to BASIC I/O AD Table of ContentsProduct Test IntroductionOverview Capacity1-2Vol.2 I/O signal compatibilityIntroduction Protocol Compatibility IntroductionAnalog Input Functions TemperatureIntroduction Available I/O functionalityRead DelayedIntroduction Digital inputsExtended capabilities IntroductionSquarewave Pulse Generator4 Position BASIC I/O AD SpecificationsIntroduction Ordering InformationANALOG INPUTS, 12 BIT IntroductionAvailable I/O Modules 1-8Vol.2Figure 2-1 BASIC I/O AD Footprint InstallationInstallation 2-2Vol.2 InstallationPower Wiring RS-485 can only be multidrop InstallationDesigning the Network Multidrop2-4Vol.2 InstallationRS-422 RS-4852-5Vol.2 InstallationRS-485 Programming 2-6Vol.2 InstallationCommunication Wiring R35 is the 1.5k from prior - bias resistor InstallationNetwork load V.S. Noise suppression R34 is the 1.5k from prior +bias resistor2-8Vol.2 InstallationNetwork Type Switches Figure 2-3 BASIC I/O AD Connectors, Switches and IndicatorsUsed in RS-422 or RS-485 networks InstallationRepeat MultidropFigure 2-7 RS-422 Host to BASIC I/O AD InstallationCommunications Wiring 2-11Vol.2 InstallationRS-485 Host to BASIC I/O AD Figure 2-8 RS-485 To-BASIC I/O AD 2-12Vol.2 InstallationBASIC I/O AD TO BASIC I/O AD RS-422 Figure 2-6 RS-422 BASIC I/O AD-To-BASIC I/O AD2-13Vol.2 InstallationBASIC I/O AD to BASIC I/O AD RS-485 Figure 2-8 RS-485 BASIC I/O AD to BASIC I/O ADBASIC I/O AD Module Placement Worksheet InstallationInstalling the I/O modules 2-15Vol.2 InstallationModule Wiring Analog Inputs Figure 2-11 AC current and voltage wiring2-16Vol.2 InstallationFigure 2-12 Analog Voltage, frequency and Current input Wiring Figure 2-13 Temperature Input Wiring2-17Vol.2 InstallationFigure 2-14 Analog Voltage and Current Output Wiring Analog outputs2-18Vol.2 InstallationFigure 2-15 Digital Input Wiring Digital Inputs2-19Vol.2 InstallationFigure 2-16 Digital output wiring Digital OutputsFunction addresses SetupChassis Setup Figure 3-17 Connectors, Switches, and Indicators Offset ModeVariable Mode SetupProtocol Handshake Types SetupNetwork Type Switch Baud RatesChanging Setup Parameters Via Pushbutton SetupU0=00 U1=40 U2=80 SetupH012 L3 P2 Address Setup Via Network -Variable mode only factor default values for an IOP-AD/3+depicted in this example3-6Vol.2 SetupHardware error codes Index Vol.2Analog Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 8, 2 - 15 Analog outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 8, 2 - 17 Baud rate . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3 Cabling costs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 1 Chassis Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1 Communications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 7 Communications watchdogs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 2 Digital Inputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8, 2 - 18 Digital Outputs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1-8, 2 - 19 Environment . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 7 Frequency . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 8 Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 2 Modules . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 8 Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 1 Multidrop . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 3, 2 - 6 Network Bias Resistors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 7 Network Type Switch . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 3 Noise suppression . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 7 Power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 7 Power Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 8 Power Wiring . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 2 Repeat . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 3 Repeater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 6 RS-422 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 7, 2 - 3, 2 - 4 RS-485 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 4, 2 - 5 RTD . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 15 Sequential display . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 1 Setup . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 4 Setup pushbutton . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3 - 1 Signal conditioning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 2 Switches . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 - 12, 2 - 13 Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 8 Thermocouple . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 - 8, 2 Index Vol.2