Elgas EDT 101 User Manual
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Elgas EDT 101 User Manual

Temperature transducer
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Temperature transducer EDT 101
User manual
Rev. 6
December 2019
1

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  • Page 1 Temperature transducer EDT 101 User manual Rev. 6 December 2019...
  • Page 2 Information in this document is subject to change without notice and does not represent a commitment on the part of ELGAS, s.r.o. Improvements and/or changes in this manual or the product may be made at any time. These changes will be made periodically to correct technical...

  • Page 3: Table Of Contents

    Contents Introduction ........................6 Device overview........................7 Available versions ........... Chyba! Záložka není definována. Technical Description ....................7 Device specification ....................8 Installation ........................11 Mechanical Installation .................... 11 Electrical installation ....................11 Cabling, grounding ....................12 Power Supply Requirements ..................13 Modbus Communication Protocol ...................
  • Page 4 4.4.4 Read EEPROM ...................... 24 4.4.5 Stop measurement....................25 4.4.6 Start single measurement..................25 4.4.7 Start continuous measurement................25 4.4.8 Unlock user configuration section ............... 26 4.4.9 Unlock service configuration section ..............26 4.4.10 Change password ..................... 26 Modbus function codes ...................
  • Page 5 Abbreviations and terms char 8-bit signed integer value Cyclical Redundancy Check Decimal representation EEPROM Electrically erasable non-volatile memory float 32-bit single precision floating point value Full scale Hexadecimal representation Modbus 16-bit signed integer value The least significant byte A vendor-neutral communication protocol intended for supervision and control of automation equipment.

  • Page 6: Introduction

    1 Introduction Temperature transducer EDT 101 (hereinafter “transducer”) is a miniature precision device intended for temperature measurement in applications which require a high precision and ultra-low power consumption. The transducer has RS 485 digital interface, which makes it ideal for use in modern digital systems.

  • Page 7: Device Overview

    2 Device overview 2.1 Technical Description Chyba! Nenalezen zdroj odkazů. shows functional diagram of the transducer. Temperature is measured by platinum resistive sensor. The signal from the sensor is converted by a high- resolution analog-to-digital converter into digital form and processed by the microcontroller. Microcontroller digitally compensates the non-linearity of the sensor using calibration data.

  • Page 8: Device Specification

    2.2 Device specification Measurement ranges Standard range: -25°C to +70°C Extended range: -40°C to +70°C Temperature sensor Platinum resistive element Pt 1000 mounted in ANSI 316L stainless-steel stem, stem diameter: 5.7 mm, stem length: 50 mm standard Measured media Liquids and gases, chemically compatible with stainless-steel ANSI 316L Accuracy 0.2°C within the full measurement range Includes non-linearity, repeatability and long-term stability.
  • Page 9 Modbus RTU, speed 38400 bit/s, 1 start bit, 8 data bits, no parity, 1 stop bit. Standard functions supported: Read holding registers (code 03h), Force single coil (code 05h) and Write holding registers (code 10h). Non-standard functions with codes 45h, 46h, 47h, 48h are implemented. Datalogging The transducer is able to measure temprature automatically in regular intervals and store the measured values in the memory to be retrieved from later on.
  • Page 10 Equipment with the “i” protection type (intrinsically safe equipment) in compliance with EN 60079-0 [4] and EN 60079-11 [5]. The certificate registered under No. FTZÚ 18 ATEX 0142X at the Physical-Technical Testing Institute Ostrava-Radvanice, notified body No. 1026. Environment classification: Zone 1, 2 according to the EN 60079-14 [6] Protection class: II1G Ex ia IIC T4 Ga Safety descriptions: = 9.9 V...

  • Page 11: Installation

    3 Installation 3.1 Mechanical Installation Temperature transducer is intended for mounting into a thermowell on piping. Operating position of the transducer is arbitrary. The depth of the thermowell must be 50 mm minimum. The transducer stem must be inserted to the very bottom of the thermowell and secured by the fastening nut against pulling-out.

  • Page 12: Cabling, Grounding

    DATA+ RS 485 Host DATA- Power Suppl ..Transducer Transducer Transducer Fig.3 Transducers connection into data network. To achieve low power consumption, the transducer uses a special RS 485 driver with limited slew rate. It is recommended to leave the RS 485 bus unterminated to maintain power consumption as low as possible.

  • Page 13: Power Supply Requirements

    3.4 Power Supply Requirements The transducer is optimized for very low-power applications. It operates from unregulated single supply voltage in range 2.8 V to 5.0 V. The supply current is independent from the supply voltage. The transducer uses an advanced algorithm to maintain the power consumption at a minimum level.
  • Page 14 The following table summarizes transducer’s typical average supply current for various measurement periods. The values include power consumption during the measurement and during necessary communication with the host to initiate the measurement and read measured values. Measurement period [s] Average supply current [µA] Continuous measurement 800 Standby...

  • Page 15: Modbus Communication Protocol

    4 Modbus Communication Protocol The following text describes implementation of the Modbus communication protocol in the transducer. In order to assure a complete understanding of the operation of the device, the user should familiarize himself with the Modbus protocol in detail in the reference literature [1].

  • Page 16: Device Specific Features

    Address field In a query frame, the address field contains a slave address. In a response frame, the address field contains the address of the responding slave device. Valid slave addresses are in the range of 1 – 247 decimal. Address 0 is reserved for broadcast messages.

  • Page 17: Holding Registers Map

    4.3 Holding Registers Map The transducer’s memory is mapped into Modbus holding registers address space (4xxxx reference). This address space can be read by the Read multiple registers (03h) command and written by the Write multiple registers (10h) command. The commands are described in chapter Chyba! Nenalezen zdroj odkazů..
  • Page 18 Holding register map overview - 2nd part Section Register Register name Data Access Stored in name number type control EEPROM 40055 – 40056 Offset trim float 40057 – 40058 Span trim float 40059 – 40061 not used 40062 Modbus slave address uchar 40063 Group assignment register...

  • Page 19: Factory Configuration Section

    4.3.2 Factory configuration section This section contains a basic information about the transducer and calibration data. The parameters are entered during manufacturing and calibration procedures and cannot be changed by the user. Hardware revision number identifies a version of the transducer’s hardware. Software revision number identifies a version of the transducer’s software.

  • Page 20: Service Configuration Section

    4.3.3 Service Configuration Section Parameters in the Service configuration section allows to adjust the offset and span of the transducer. The default parameters are entered during calibration procedure and can be changed only by an authorized person using Service password. Offset trim is an additive constant which defines the shift of the transducer characteristics relative to the factory calibration data.
  • Page 21 Primary channel direct readout store value measured directly by the analog-to-digital converter for the primary channel. The value is presented for factory purposes and it is not significant for user. Auxiliary channel direct readout store value measured directly by the analog-to-digital converter for the auxiliary channel (not used for temperature measurement).

  • Page 22: Datalogger Section

    Status register stores information about transducer’s status. Description of the particular bits is given in the following table: Name Description EEPROM error The bit is set if the internally generated EEPROM checksum does not match the stored value. Possible malfunction of the transducer may be expected in this case (see sections 4.4.3 and 4.4.4) Sensor error The bit is set if sensor or AD converter failure is detected.

  • Page 23: Data Types

    Delay stores copy of the Delay parameter passed by the Synchronize Datalogging command. Period stores copy of the Period parameter passed by the Synchronize Datalogging command. Number of samples gives the actual number of samples stored in the Data memory. Data registers store temperature samples measured during datalogging.

  • Page 24: Discrete Outputs Map

    4.4 Discrete outputs map Discrete outputs (coils) can be set by the Force single coil (05h) command. Discrete outputs address space is accessible only for writing. Reading is not supported. Physically, the transducer does not have any discrete outputs. Discrete outputs address space is implemented to allow access to several functions.

  • Page 25: Stop Measurement

    4.4.5 Stop measurement. Forcing the Stop measurement coil ON stops the single measurement, continuous measurement or datalogging if this is in progress, otherwise the function has no effect. 4.4.6 Start single measurement. Forcing the Start measurement coil ON starts a single measurement of temperature. The query is responded immediately, but the measurement takes 120 ms.

  • Page 26: Unlock User Configuration Section

    4.4.8 Unlock user configuration section Forcing the Unlock user configuration section coil ON when the correct value is written in the Password registers unlocks the user configuration section of registers 40062 – 40066 for write operation. To unlock and write into the User configuration section, the following procedure has to be executed: 1.
  • Page 27 To change user password, the following procedure has to be executed: 1. Write the old password into registers 40067 – 40068 using the Write multiple registers command. 2. Force coil 0017 (Unlock user configuration section) ON. If the password is correct, the normal response is returned and the change password function is enabled.

  • Page 28: Modbus Function Codes

    4.5 Modbus function codes Three standard function codes are implemented to access the transducer’s memory and simple functions: Function code (hex) Function Read multiple registers Force single coil Write multiple registers Four non-standard function codes are implemented to allow easy and efficient access to special functions of the transducer: Function code (hex) Function...

  • Page 29: Force Single Coil (05H)

    The response contains data read from the specified registers. The register data in the response message are packed as two bytes per register. For each register, the first byte contains the most significant byte and the second contains the least significant byte. An example of the response to the query: Byte no.

  • Page 30: Write Multiple Registers (10H)

    The normal response is an echo of the query. Here is an example of the response to the query shown above: Byte no. Field name Example (hex) Slave address Function code Coil address (Hi) Coil address (Lo) Force data (Hi) Force data (Lo) CRC (Lo) CRC (Hi)

  • Page 31: Start Measurement With Mask (45H)

    The normal response returns the slave address, function code, starting address, and number of registers written. Here is an example of the response to the query shown above: Byte no. Field name Example (hex) Slave address Function code Starting register (Hi) Starting register (Lo) Number of registers (Hi) Number of registers (Lo)

  • Page 32: Synchronize Datalogging (46H)

    4.5.5 Synchronize datalogging (46h) The transducer is able to automatically measure temperature in preset time intervals and store the values into the registers 40088 - 40167 (datalogging). Synchronize Datalogging command can be used to start or re-synchronize the datalogging. The query specifies Period parameter which describe measurement timing. If no datalogging is in progress, the Synchronize Datalogging command starts it.

  • Page 33: Erase Data (47H)

    Here is an example of the request to start / synchronize datalogging for the transducer with slave address 11h. The measurement period is 1 s. Byte no. Field name Example (hex) Slave address Function code not used not used Period (Hi) Period (Lo) CRC (Lo) CRC (Hi)

  • Page 34: Set Slave Address (48H)

    Response to the query: Byte no. Field name Example (hex) Slave address Function code Number of remaining samples CRC (Lo) CRC (Hi) 4.5.7 Set slave address (48h) This function allows to set a slave addresses of the particular transducer in case that multiple transducers are connected to the same bus.

  • Page 36: Exception Responses

    4.6 Exception responses When a master device sends a query to a slave device it expects a normal response. One of four possible events can occur from the master’s query:  If the slave device receives the query without a communication error and can handle the query normally, it returns a normal response.
  • Page 37 Function 01h (Read coil status) is not supported by the transducer. The transducer will return the exception response with the exception code Illegal function (01). Byte no. Field name Example (Hex) Slave address Function code Exception code CRC (Lo) CRC (Hi) List of exception codes supported by the transducer: 01 Illegal function The function code received in the query is not an allowable action for the slave.

  • Page 38: Related Publications

    5 Related Publications Modicon Modbus Protocol Reference Guide, Modicon Inc., Industrial Automation Systems, 1996 ČSN EN 61000-6-2 ed.3: 2006, Electromagnetic compatibility (EMC) – Part 6-2: Generic standards – Immunity for industrial environments ČSN EN 60068-2-6 ed.2: 2008, Environmental testing - Part 2-6: Tests - Test Fc: Vibration (sinusoidal) ČSN EN 60079-0 ed.4: 2013 + A1:2014+Rev.2:2014, Explosive atmospheres - Part 0: Equipment - General requirements...
  • Page 39 Temperature Transducer EDT 101 Jan Věříš Author: published: ELGAS, s.r.o. tel.: +420 466 414 500, 511 Ohrazenice 211 fax: +420 466 411 190 533 53 Pardubice http://www.elgas.cz Czech Republic e-mail: sales@elgas.cz Date: December 2019 Edition: H101AN_201912_EDT101...
  • Page 40 H101AN_201912_EDT101...

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