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Vertex VT26 Series Instruction Manual

Rs-485 communication, modbus protocol reference guide
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VT26/30 SERIES CONTROLLERS (VERSION 6.0)
RS-485 COMMUNICATION INSTRUCTION MANUAL
MODBUS Protocol Reference Guide
1.1 General ------------------------------------------------------------------------- 1
2.1 Communication Specifications ----------------------------------------- 1
3.1 Terminal Allocation --------------------------------------------------------- 2
3.2 Wiring --------------------------------------------------------------------------- 2
4.1 Set Items ----------------------------------------------------------------------- 3
4.2 Setting Operation Method ------------------------------------------------ 3
5.1 General ------------------------------------------------------------------------- 4
----------------------------------------------- 4
5.3 Response of Slave Station ----------------------------------------------- 5
5.4 Function Code --------------------------------------------------------------- 6
5.6 Transmission Control Procedure -------------------------------------- 6
7.1 Data Format ------------------------------------------------------------------- 9
7.2 Data Address Map ---------------------------------------------------------- 11
8.1 Troubleshooting ------------------------------------------------------------- 14

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  • Page 1: Table Of Contents

    VT26/30 SERIES CONTROLLERS (VERSION 6.0) RS-485 COMMUNICATION INSTRUCTION MANUAL MODBUS Protocol Reference Guide 1. COMMUNICATION FUNCTIONS 1.1 General ------------------------------------------------------------------------- 1 2. SPECIFICATIONS 2.1 Communication Specifications ----------------------------------------- 1 3. CONNECTION 3.1 Terminal Allocation --------------------------------------------------------- 2 3.2 Wiring --------------------------------------------------------------------------- 2 4. SETTING OF COMMUNICATION CONDITION 4.1 Set Items ----------------------------------------------------------------------- 3 4.2 Setting Operation Method ------------------------------------------------ 3 5.

  • Page 2: Communication Functions

    1. COMMUNICATION FUNCTIONS 1.1 General VT26/30 series provides a communication function by RS-485 interface, by which it can transmit and receive data to and from host computer, programmable controller, graphic display panel, etc. The communication system consists of master station and slave stations. Up to 255slave station can be connected per master station.

  • Page 3: Connection

    3. CONNECTION △ WARNING For avoiding electric shock and malfunctions, don’t turn on the power supply until all wiring has been completed. 3.1 Terminal Allocation VT-9626 / VT-9630 Terminal number Signal name VT-9426 Terminal number Signal name VT-4926 / VT-4930 Terminal number Signal name VT-7226 / VT-7230...

  • Page 4: Setting Of Communication Condition

    4. SETTING OF COMMUNICATION CONDITION In order that the master station and VT26/30 series can correctly communicate, following settings are required. All communication condition settings of the master station are the same as those of VT26/30 series. All VT26/30 series connected on a line are set to address (ADDR), which are different from each other.

  • Page 5: Modbus Communication Protocol

    9.6K △ or ▽ Press △ or ▽ key to setting “BAUD=9.6K” BAUD 9.6K Press SET key to save “BAUD”. BAUD 9.6K SET + BACK Press SET + BACK one time to return the normal indication (PV/SV indication). 5. MODBUS COMMUNICATION PROTOCOL 5.1 General The communication system by the MODBUS protocol is that the communication is always started from the master station and a slave station responds to the received...

  • Page 6: Response Of Slave Station

    response, it places its own address in this address field of the response to let the master know which slave is responding. Address 0 is used for the broadcast address, which all slave stations recognize. When the broadcast address (address 0) is applied on the command message, no any response message will be sent from the slave stations.

  • Page 7: Function Code

    Illegal data value A value contained in the data field is not an allowable value for the slave. 5.4 Function Code The listing below shows the function codes supported by VT20 series controllers. Function code Code Function Object Read-out Holding Register Read-out Input Register Write-in...

  • Page 8: Details Of Message 6.1 Read-Out Of Word Data [Function Code: 03]

    1-5. For ensuring the safety, make a confirmation of the response message and make an arrangement so as to provide 3 or more retries in case of no response, error occurrence, etc. Note: The above definition is for most unfavorable value. For ensuring the safety, it’s recommended the program of the master to work with safety factors of 2 to 3.

  • Page 9: Read-Out Of Read-Only Word Data [Function Code: 04]

    Address Function Byte Number * Word Data CRC-16 01 ~ FF 02~FC Low-order byte High-order byte 1 byte 1 byte 1 bytes N bytes 2 bytes * Byte number = Word number × 2 2. Message transmission (example) The following show an example of reading the Setpoint Value (1000) from address No.1 controller.

  • Page 10: Write-In Of Word Data (1 Word) [Function Code: 06]

    6.3Write-in of Word Data (1 word) [Function Code: 06] 1. Message composition Command message composition Address Function Starting Address Word Data CRC-16 1 ~ FF 0xxx 0xxx Low-order byte High-order byte 1 byte 1 byte 2 bytes 2 bytes 2 bytes Response message composition Address Function Starting Address Word Data...
  • Page 11 (55 × 60) ＋ 30 = 3330 (sec.) Index code: Some parameters value are set by index code. For example, to change the unit to ℃ via communication. The data value would be 0017(hex). Code English Code English Code English Code English Code English None 0000 PROG...

  • Page 12: Data Address Map

    7.2 Data Address Map Word data (read-out/write-in) : Function code [03,06] Data Address Parameter Range Unit 0000 HiLt~LoLt ℃/℉ 0001 A1SP -1000~1000 ℃/℉ 0002 A2SP -1000~1000 ℃/℉ 0003 Yes.1/Yes.2/No (English code) 0004 HAND Yes/No (English code) 0005 OUTL -100.0~100.0 0006 Hold/Go/Stop (English code) 0007 PROG...
  • Page 13 0023 A1MD None/Stdy/Lath/St.La/T.End (English code) 0026 Ptn1 / Ptn2 (English code) 0027 BAND 0~1000 ℃/℉ 0028 LoLt~HiLt ℃/℉ 0029 End/00.00~99.59 HH.MM/MM.SS 002A 00.00~99.59 HH.MM/MM.SS 002B LoLt~HiLt ℃/℉ 002C End/00.00~99.59 HH.MM/MM.SS 002D 00.00~99.59 HH.MM/MM.SS 002E LoLt~HiLt ℃/℉ 002F End/00.00~99.59 HH.MM/MM.SS 0030 00.00~99.59 HH.MM/MM.SS 0031...
  • Page 14 004D RT13 End/00.00~99.59 HH.MM/MM.SS 004E ST13 00.00~99.59 HH.MM/MM.SS 004F SP14 LoLt~HiLt ℃/℉ 0050 RT14 End/00.00~99.59 HH.MM/MM.SS 0051 ST14 00.00~99.59 HH.MM/MM.SS 0052 SP15 LoLt~HiLt ℃/℉ 0053 RT15 End/00.00~99.59 HH.MM/MM.SS 0054 ST15 00.00~99.59 HH.MM/MM.SS 0055 SP16 LoLt~HiLt ℃/℉ 0056 RT16 End/00.00~99.59 HH.MM/MM.SS 0057 ST16 00.00~99.59...

  • Page 15: Troubleshooting

    0075 2-07 00~16 (English code) 0076 2-08 00~16 (English code) 0077 2-09 00~16 (English code) 0078 2-10 00~16 (English code) 0079 2-11 00~16 (English code) 007A 2-12 00~16 (English code) 007B 2-13 00~16 (English code) 007C 2-14 00~16 (English code) 007D 2-15 00~16 (English code)

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Vt30 series

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