Dräger Polytron 8000 Series Technical Manual
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Dräger Polytron 8000 Series Technical Manual

Digital communication - modbus rtu
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Technical Manual
Digital Communication -
Modbus RTU
Dräger Polytron® 8000 Series

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Summary of Contents for Dräger Polytron 8000 Series

  • Page 1 Technical Manual Digital Communication - Modbus RTU Dräger Polytron® 8000 Series...
  • Page 2 This page has been left blank intentionally. Technical Manual...

  • Page 3: Table Of Contents

    Contents Contents ® Digital Communication - Modbus RTU Dräger Polytron 8000 Series Introduction ....................Target group ................... General safety statements.............. Meaning of the warning notes............Trademark ..................Basic principles of the Modbus technology .......... Definition of the Modbus protocol ........... System overview................

  • Page 4: Introduction

    Introduction Introduction This document is a supplement to the instructions for use for the following gas detectors: ® – Dräger Polytron 8100 EC ® – Dräger Polytron 8200 CAT ® – Dräger Polytron 8310 IR ® – Dräger Polytron 8700 IR ®...

  • Page 5: Basic Principles Of The Modbus Technology

    Basic principles of the Modbus technology Basic principles of the Modbus technology Definition of the Modbus protocol The Modbus protocol was developed by Modicon in 1979. It is an open, standardized communications protocol which is used in production, process, or building automation.
  • Page 6 Basic principles of the Modbus technology 2.2.1 Topology Request of the Master Response from a Slave Master Slave Slave Slave Minimum configuration A Modbus system consists of at least the following components: – A Modbus Master to control the data traffic. –...
  • Page 7 Basic principles of the Modbus technology 2.2.2 Transmission technology RS-485 RS-485 is the most common transmission technology. It uses a shielded, twisted 2- wire line. Transmission rates between 9600 bit/s and 115200 bit/s can be selected. It is defined when commissioning the system and is the same for all devices connected to the bus.

  • Page 8: Data Transmission

    Basic principles of the Modbus technology Data transmission There are 3 different data transmission modes in a Modbus system: – Modbus ASCII – Modbus RTU – Modbus TCP In Modbus ASCII, data is not transmitted as a binary sequence, but as ASCII code. The data is directly human-readable, but the data throughput is lower than in Modbus RTU.
  • Page 9 Basic principles of the Modbus technology Application layer – layer 7 The application layer provides functions for the application. It forms the connection to the lower layers. Software for communication within the scope of the specific application (measuring system, etc.) is provided by the manufacturers. In addition, there are a number of terminal programs to enable communication between the participants in a Modbus network.
  • Page 10 Basic principles of the Modbus technology The following transmission rates are available for RS-485 applications: 1200 bit/s 2400 bit/s 4800 bit/s 9600 bit/s 19200 bit/s 38400 bit/s 56000 bit/s 115200 bit/s Operating principle Communication in a Modbus network follows a simple request/response mechanism: the Master (1) sends a request (Telegram) (2) to the Slave (4).
  • Page 11 Basic principles of the Modbus technology Communication in the Modbus network occurs through so-called polling. The Master sends a telegram (Request) to the Slave. It then receives the Response. Data transmission in Modbus RTU is in binary format. A data telegram consists of several blocks (Frames): –...
  • Page 12 Basic principles of the Modbus technology Function code The function code specifies the purpose of the data transmission. It defines the command to be executed by the Slave. Com- Function code Description mand Read Coils Read back several digital outputs Read Discrete Inputs Read several digital inputs Read Holding Registers...
  • Page 13 Basic principles of the Modbus technology Error Error code 1 byte 0x83 Exception code 1 byte 01 or 02 or 03 or 04 FC16 Write Multiple Register Request Function code 1 byte 0x10 Starting address 2 byte 0x0000 to 0xFFFF Number of registers 2 byte 0x0001 to 0x007B...
  • Page 14 Basic principles of the Modbus technology – Function code – Error code (Exception Code) – CRC (checksum) To mark the error message, the leading bit of the returned function code is set. The error code (Exception Code) is used to transmit the error cause to the Master. Excep- Description tion code...

  • Page 15: Installation

    Installation Installation The following chapters describe the installation and configuration of the ® Dräger Polytron 8000 gas detector with Modbus RTU interface (hereafter referred to as "gas detector"). Technical data The following values apply for the gas detector: Parameter RS-485/EIA485 Number of receivers Maximum line length 1000 m...

  • Page 16: Pin Assignment

    Installation 3.2.2 Cable lengths The following factors influence the cable length – Transmission rate – Cable type – Number of directly connected devices (series connection) – Network configuration (2-wire or 4-wire) The maximum line length is 1000 m, at a transmission rate of 19200 bit/s. It depends on the data transmission speed and the number and lengths of the individual leads.
  • Page 17 Installation 3.3.2 Signal lines for explosion protection type Ex d The terminal of the PCB unit within the Ex d housing is assigned as follows: + / Data A DATA A - / Data B DATA B Ground Ground Shield 4-pin connector Assignment Data-A...

  • Page 18: Termination

    Installation 3.3.3.1 Rewiring of the PCB unit in the Ex d housing The following information is only required if the Ex d housing has to be rewired (e.g. when replacing the PCB unit in the Ex d housing). Remote sensor Data-A Data-B Shield...

  • Page 19: Opening The Gas Detector

    Installation Turning the termination on and off To turn the termination on, slide the sliding switch towards the center of the PCB. To turn the termination off, slide the sliding switch towards the edge of the PCB. Sliding switch for termination (indicated position: termination turned on) Opening the gas detector 1.

  • Page 20: Connecting The Gas Detector

    Installation Connecting the gas detector Preconditions: – Cable bushings are installed at the gas detector as described in the respective instructions for use. 1. Insert the fieldbus cable and the power supply cable into the cable bushing. 2. Strip the cores of the cables. 3.

  • Page 21: Commissioning

    Commissioning Commissioning Checking installation and operation Check the connections and cables for correct wiring prior to commissioning. Faulty connections can damage the gas detector. Check the following prior to commissioning: 1. Are all cables connected properly? 2. Is voltage in the range from 10 to 30 V applied? Configuring the RS-485 interface The following settings are preset for the Modbus RTU transmission.

  • Page 22: Configuring The Gas Detector

    Commissioning – If the software address assignment is changed while the hardware address assignment is active, the software address assignment is saved. The saved change only becomes valid when the software address assignment is selected. Configuring the gas detector 4.3.1 Defining communication settings at the gas detector To define communication settings at the gas detector, proceed as follows: 1.
  • Page 23 Commissioning 4. Turn the gas detector on and off (power cycle). The gas detector must be turned on and off for the changes to the DIP switch to be accepted. If the address assignment is selected using the DIP switch, the address set on the DIP switch is used when restarting the field device.
  • Page 24 Commissioning 4.3.4 Configuring the connection In addition to the display, Dräger offers a freely available software (DTM Device Type Manager) to commission, configure and diagnose the gas detector via the Modbus-RTU interface. Software and tools Obtain the software components for configuration from www.draeger.com. Use the Field Device Tool (FDT) to configure and control the gas detector.
  • Page 25 Commissioning 4.3.4.1 Configuring communication DTM (COM_DTM) 1. Open Control Panel. 2. Open Device Manager. 3. Open Ports (COM & LPT): Check the COM port used for the Modbus interface. 4. Open the "fdtCONTAINER" program. 5. Select Empty project.  The network view on the left shows a tree structure. 6.
  • Page 26 Commissioning If all settings are correct, the connection status (1) changes to verbunden/connected. Technical Manual Digital Communication - Modbus RTU...

  • Page 27: Integration Into Process Control Systems

    Integration into process control systems Integration into process control systems General information Gas detectors can be quickly and easily connected to process control systems via a digital Modbus RTU interface. They allow the cyclic capturing of measured values, status information and the full configuration of the gas detector in remote operation. 5.1.1 Serial reading and writing ®...

  • Page 28: Reading The Gas Concentration

    Integration into process control systems Changing passwords There are 2 parameters for changing passwords. Both parameters are 4 registers long. In the first two registers, the current password is requested, and in the other two registers, the new password is set. Password Parameter Register...

  • Page 29: Reading Diagnostic And Status Information

    Integration into process control systems If the telegram has been transmitted without errors via the physical medium, the gas detector answers with the following telegram contents: Slave address Function Number of Data code transmitted bytes 0x03 0x03 0x04 0x42 0x20 (register: 40507) 0xCC 0x00 0x00 (register: 40508) 0x41...
  • Page 30 Integration into process control systems The DEVICE_STATUS_INDICATION parameter provides a quick overview of the current status of the gas detector. For further information and possible remedies, read the DEVICE_STATUS_VALUE parameter in register 40024. The parameter consists of 10 registers (20 bytes) and is read-only. The register range from 40024 to 40028 contains a warning matrix consisting of 10 bytes (W09 to W00).
  • Page 31 Integration into process control systems Register: 40030 0x00 0x00 Register: 40031 Bit15 Bit14 Bit13 Bit12 Bit11 Bit10 Bit09 Bit08 Bit07 Bit06 Bit05 Bit04 Bit03 Bit02 Bit01 Bit00 DEVICE_STATUS_VALUE[05]=E5 DEVICE_STATUS_VALUE[04]=E4 E.g.: DEVICE_STATUS_VALUE=0x02 0x00 0x00 Register: 40032 Bit15 Bit14 Bit13 Bit12 Bit11 Bit10 Bit09 Bit08 Bit07 Bit06 Bit05 Bit04 Bit03 Bit02 Bit01 Bit00 DEVICE_STATUS_VALUE[03]=E3 DEVICE_STATUS_VALUE[02]=E2 E.g.: DEVICE_STATUS_VALUE=0x02...

  • Page 32: Reading The Date And Time

    Integration into process control systems Reading the date and time The DEVICE_DATE_TIME parameter shows the time and date in the gas detector. The parameter is 4 registers long and starts in register 40034. The following tables show the parameter using 18:04:31000 / 2015-01-23 as an example.

  • Page 33: Troubleshooting

    Troubleshooting Troubleshooting Error analysis If communication with the gas detector cannot be established, check the settings of the following parameters: – Address – Port (COM port) – Baud rate – Parity – Stop bits – Termination The parameters in the gas detector and in the communication DTM have to match to establish a connection.
  • Page 34 Troubleshooting Byte Value Error description Remedy 0x04 Dräger measuring mode check- sum error 0x08 Dräger status checksum error 0x10 Dräger 4 to 20 mA checksum error 0x20 User Data Logger checksum error 0x40 User menu checksum error 0x80 User Real Time Clock checksum error 0x01 tbd.
  • Page 35 Troubleshooting Byte Value Error description Remedy 0x20 No sensor connected Replace sensor Disconnect and reconnect sensor 0x40 Incorrect sensor version con- Replace sensor nected 0x80 Incorrect sensor type connected Replace sensor 0x01 Unknown measuring unit Perform sensor init. Replace sensor 0x02 Measured value fallen below the Perform zero adjustment...
  • Page 36 Troubleshooting Byte Value Error description Remedy 0x80 Parameters for measuring mode Replace sensor switches are not supported 0x01 No extension block present in the Replace sensor sensor 0x01 The sensor transmits its fault sig- 0x02 Sensor test failed Replace sensor 0x02 Basic initialization required 0x02...
  • Page 37 Troubleshooting Byte Value Error description Remedy 0x20 CRC error in EX-specific EC sen- sor data 0x20 Data inconsistency at PIR 7x00. Value does not equal string. 0x40 SIL password from PIR 7x00 does not have the default value 0x01 MB warning (group error) 0x02 Temperature too low Replace sensor...
  • Page 38 Troubleshooting Byte Value Error description Remedy 0x01 Error when writing to the sensor data set Technical Manual Digital Communication - Modbus RTU...

  • Page 39: Annex

    Annex Annex Glossary Abbrevia- Name Meaning tion ASCII American Standard 7-bit character encoding that corresponds Code for Information to the US version of ISO 646. Interchange It is the basis for later encodings for char- acter sets that are based on more bits. Baud rate Symbol rate.
  • Page 58 Manufacturer Dräger Safety AG & Co. KGaA Revalstraße 1 D-23560 Lübeck Germany +49 451 8 82-0 +49 451 8 82-2080 http://www.draeger.com Á9033781VÈ 9033781 – IfU 4683.800 en © Dräger Safety AG & Co. KGaA Edition: 02 – 2019-01 (Edition: 1 – 2016-06) Subject to alteration...

This manual is also suitable for:

Polytron 8100 ecPolytron 8200 catPolytron 8310 irPolytron 8700 irPolytron 8720 ir

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