ABB SM2000 User Manual

Also see for SmartMedia SM2000: Installation instructions User guide supplement User guide User guide User guide supplement

Contents

ABB SM2000 User Manual Manual pdf 91 page image

89edoC emaN noitinifeD10 noitcnuFlagellI tonsideviecernoitcnufegassemehTnoitcaelbawollana20 ataDlagellIsserddAdleifatadehtniecnerefersserddaehTsserddaelbawollanatonsi30 eulaVataDlagellI sidleifatadehtnidecnerefereulavehTevalsdesserddaehtnielbawollaton70 evitageNtnemgdelwonkcA rorreegassemdevieceR80 ytiraPyromeMrorrEenonirorrenasetacidnikcehcytiraPdeviecersretcarahcehtfoeromrotupnIgolanA lioCsubdoMdeliaftupnI=1,KOtupnI=0.ylnOdaeR1A 10002A 20003A 30004A 40005A 50006A 60001B 70002B 80003B 90004B 01005B 11006B 2100devreseR 0500ot3100APPENDIX 2 – MODBUS GUIDETable A2.1 Modbus Exception ResponsesTable A2.2 Analog Input Fail StatesA2.1 IntroductionThis instrument is fitted with a Modbus/RS485 serialcommunications link as standard.The instrument is designed to act as a Remote Terminal Unit(RTU) slave when communicating with a master (host) system.A2.2 Setting Upa) Connect the instrument to a Modbus link – see Section 5.5.b) Set the RS485 configuration parameters – see Section 4.4.6.c) Add the instrument to the link configuration on the hostsystem – refer to information supplied with the host system.A2.3 Modbus Commands SupportedThe following Modbus commands are supported:01 Read Coil Status – reads the on/off status of 16consecutive digital states, starting at a specified address.The instrument returns zeros for points which do not containdefined data03 Read Holding Registers – reads 8 consecutive anologvalues, starting from a specified address. The instrumentreturns zeros for registers which do not contain defined data.05 Force Single Coil – sets the value of a single coil (digitalsignal) at the specified address. The data value must beFF00 Hex to set the signal ON and zero to turn it OFF. Theinstrument returns an exception response if the register isnot currently writeable.06 Preset Single Register – sets the value of a single register(analog value) at the specified address. The instrumentreturns an exception response if the register is not currentlywriteable. Limits defined in configuration are applied to thevalue before storage.08 Loopback Diagnostic Test – used to test the integrity ofModbus transmissions. The instrument returns the messagerecieved.15 Force Multiple Coils – the instrument carries out updatesthat are valid and returns an exception response if any of thecoils are not currently writeable.16 Preset Multiple Registers – the instrument carries outupdates that are valid and generates an exception responseif any of the registers are not currently writeable.Note.• Negative numbers are represented in '2'scomplement' format, e.g 1000 = 03E8 (Hex), –1000= FC18 (Hex)• The instrument cannot accept a new message untilthe current message has been processed and areply sent to the master (maximum response time50ms).• The instrument monitors the elapsed time betweenreceipt of characters from the host. If the elapsedtime between two characters is 3.5 character times,the slave assumes the second character received isthe start of a new message.A2.4 Modbus Exception ResponsesIf the instrument detects one of the errors listed in Table A2.1while receiving a message from the host system, it replies with aresponse message consisting of the instrument's Modbusaddress, the function code, the error code and error checkfields.A2.5 Operating Mode Modbus CoilsTables A2.2 to A2.7 detail the contents of each Modbus coil.Each coil is assigned a register that can have one of two values:0000 and 0001.