Riken Keiki SD-3 Series Operating Manual
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Riken Keiki SD-3 Series Operating Manual

Riken Keiki SD-3 Series Operating Manual

Rs-485 (modbus-rtu), communication function
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PT2E-3640
SD-3 Series
RS-485 (Modbus-RTU)
Communication Function Operating Manual

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Summary of Contents for Riken Keiki SD-3 Series

  • Page 1 PT2E-3640 SD-3 Series RS-485 (Modbus-RTU) Communication Function Operating Manual...
  • Page 2 Be sure to also read the operating manuals for the associated equipment. ● Disclaimer RIKEN KEIKI rejects all liability for the consequences of the use of device software that communicates with the product. ● Notations Notations used for numbers Base 10: Numbers only (e.g., 1, 100, 1,000)

  • Page 3: Table Of Contents

    Contents 1. Basic Information ꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏ 1 2. Register Map ꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏ 2 SD-3 Series Modbus register map ꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏ 2 Status data operation table ꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏ 4 3. Communication Specifications ꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏ 5 SD-3 Series communication specifications ꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏ 5 Modbus protocol communication specifications ꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏꞏ 6 4.

  • Page 4: Basic Information

    This section describes basic information for using SD-3 Series RS-485 (Modbus-RTU) communication functions. ● Address setting The SD-3 Series Modbus address can be set to between 1 and 128. ● Number of simultaneous connections Up to 127 devices can be connected simultaneously (when connected to one upstream master device).

  • Page 5: Register Map

    2. Register Map ● SD-3 Series Modbus register map Address Item Description Bits 0 to 1: Magnification (0: same; 1: 1/10; 2: 1/100; 3: 1/1,000) Bits 2 to 3: Units (0: vol%; 1: %LEL; 2: ppm; 3: ppb) Bit 4: Double range measurement information (1: L side;...
  • Page 6 Address Item Description Signed integer The significant figure of the resolution rounded to the nearest 40017 Resolution integer. The actual resolution is obtained by multiplying this value by bits 0 to 1 of address 40001 (magnification) or by the value at address 40018. 40018 Decimal point 0: same;...

  • Page 7: Status Data Operation Table

    Status data operation table (address 40001) ● Status 15 14 13 12 11 10 3, 2 1, 0 Normal: 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 〇 Measurement Alarm: 1st 〇 〇 〇 〇 〇 〇 〇 ● 〇 〇 〇 〇 Alarm: 2nd 〇...

  • Page 8: Communication Specifications

    3. Communication Specifications ● SD-3 Series communication specifications Item Specifications Electrical specifications Complies with EIA RS-485 standard. Communication method 2-wire half-duplex Synchronization method Asynchronous Connection form Maximum number of connected 127 devices devices (with one upstream device connected) Protocol Modbus-RTU...

  • Page 9: Modbus Protocol Communication Specifications

    ● Modbus protocol communication specifications The Modbus communication method allows communication with multiple slave devices using master/slave communication. A communication start message is sent from the master, and the slave returns a reply message in response. Modbus-RTU mode message frame Address Function Data...

  • Page 10: Appendix

    4. Appendix ● Address setting method ▲ key MENU key ▼ key SET key Setting procedure ① Press and hold the MENU key to switch to maintenance mode. (The display changes to [1-0].) ② Press the ▲ or ▼ key to display [1-3], then press the SET key. (The display changes to [-----].) ③...

  • Page 11: Wiring Method And Terminating Resistor Setting Method

    ● Wiring method and terminating resistor setting method Unscrew the single M4 hex socket set screw on the main unit cover, then rotate the cover counterclockwise to remove. Use a hex key wrench (2 across flats) to unscrew the M4 hex socket set screw. Be careful to avoid dropping the cover while unscrewing and removing it.
  • Page 12 Pull out the terminal plate (TN2 (RS-485)) from the terminal plate board. Set the terminating resistor to ON only for the device connected at the furthest position on the bus. Do not set the terminating resistors to ON for any other devices. Terminal No.
  • Page 13 NOTE When branching the RS-485 communication wiring, keep the branches short. Long branches may lead to communication failure. PLC, etc. (master) SD-3 (slave) Terminating resistor Keep branch lengths Keep branch lengths short. short. SD-3 (slave) SD-3 (slave) 10/11...

  • Page 14: Example Communication Procedure

    ● Example communication procedure Example control station (e.g., PLC) communication procedure 30 ms wait if A2 ≠ A1 30 ms wait Address: A1 Address: A2 (of next round) if A1 ≠ A2 Send Receive Send Receive query response query response No response (timeout) No response (timeout) OR communication check error...
  • Page 15 Revision history Issue Revision details Issue date First issue Mar 3, 2025...

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