DT80 range Modbus capability David Williams Product Development Manager 23 March 2010

Introduction to Modbus What is Modbus? Is an serial data protocol for transferring data between intelligent devices. Widely used in industrial sector Designed to be scalable in size and complexity. Supported in SCADA (Supervisory Control And Data Acquisition) applications Has a Master (Client) that requests data from Slave (Server) devices

Introduction to Modbus Modbus can operate using a broad range of communications media. Serial connection are typically RS232, RS422 or RS485 TCP/IP network, which can use a variety of physical link types e.g. Ethernet wireless, fibre-optic, serial (PPP) There are two methods of data transfer Modbus RTU (Remote Telemetry Unit) Binary data in packet format Most common implementation Modbus ASCII Plain text in packet format (Little used)

Introduction to Modbus Modbus Serial One master per network Each network can have up to 247 slave devices 1 slave device for RS232 Each slave device has a unique address (1 to 247) Modbus TCP/IP Multiple masters on one network Slave devices identified by TCP/IP address.

Introduction to Modbus The master device requests data from the slave Message includes; Slave address Function codes; 0 = Read a coil (e.g. Read / write the state of a digital channel) 1 = Read state 3 = Input register (Read a register) 4 = Output register (Read or write to a register.) Starting address of registers to be accessed Number of registers 16 bit check sum

Introduction to Modbus Slave device will respond only to messages direct to it. Slave devices can have up to 65535 registers Registers can be either coils (bit state) or data Data can be of types; Signed 16 bit integer Unsigned 16 bit integer Signed 32 bit integer Unsigned 32 bit integer 32 bit floating point number Maximum message length is 255 bytes This means you need to understand the device configuration and mapping

DT80 Range Modbus capability Generic implementation No special drivers required for SCADA packages Ease of integration into existing SCADA systems Supports standard Modbus data types Flexible communications Can support non standard baud rates and other communications settings (Parity, TCP/IP ports etc) Can be simultaneously connected to more than one Modbus network Can be a master and slave simultaneously on different networks

DT80 Range Modbus capability Example; Can be a master on an serial sensor port RS485 network and a slave on the RS232 host port Can be a master and a slave on a TCP/IP network

DT80 Range Modbus capability The DT80 supports Modbus master or slave modes over RS232 - Serial sensor port and Host port RS422 - Serial sensor port RS485 - Serial sensor port TCP/IP - Ethernet or PPP On a TCP/IP network a DT80 can be both a master and a slave device at the same time.

DT80 Range Modbus capability Unusual capabilities Back filling data in to SCADA systems SCADA systems are real time. If the network or power fails then data is lost. The DT80 having independent power will keep data that can be recovered latter. Independent alarming. The DT80 has the capability to send alarms independent of SCADA system Gateway Modbus to Modbus SDI-12 to Modbus Serial to Modbus CAN to Modbus (e.g. OBDII, J1939)

DT80 Range Modbus capability Unusual capabilities FTP Client - Can push data to a site FTP Server - Can serve data when requested High quality web interface built in as standard Custom web pages Allows real time inter logger calculations and data exchange.

DT80 Range Modbus Slave configuration Introduced in V6.02 firmware (May 2006) Modbus registers mapping Channel variables - Registers 1 to 1000 System variables - Registers 4001 to 4053 Digital I/O and relay - Registers 8000 to 8009 Note: Modbus master can access digital i/o directly Data types supported Signed 16 bit integer Unsigned 16 bit integer Signed 32 bit integer 32 bit floating point number

DT80 Range Modbus Slave configuration Slave commands and settings SetModBus Used to set the data type in the registers Profile settings Allow the DT80 to be configured to suit Modbus network Set communications interface to slave mode Note: Modbus ASCII is not supported

DT80 Range Modbus Master configuration Example of code Begin“Slave" SETMODBUS 1..2CV MBI 100 'Configure Modbus registers for temperature readings RA("B:",Data:NOV:60D)1M ' Measure concrete temperature - 2 thermocouples per channel on CEM20 #1 101*TT(=1CV,"Temp1~DegC",ff2) 'Temperature 1 mapped to MODBus register 1 101TT(=2CV,"Temp2~DegC",ff2) 'Temperature 2 mapped to MODBus register 2 END

DT80 Range Modbus Master configuration Introduced in V8 firmware (March 2010) New channel type nMODBUS(Options)(=Assign) Access to the different communications interfaces 1 = Serial sensor port 2 = Host port 4 = TCP/IP

DT80 Range Modbus Master configuration Channel options; Allow read / access to all Modbus functionality Assign (Option) Writing data to single or multiple registers - =x..xxCV Profile settings To configure DT80 to match Modbus network Set communications interface to master mode Error messages and diagnostics Full error reporting will 11 new error messages Diagnostics for Modbus added

DT80 Range Modbus Master configuration Example of code Begin"Master" RA1M '======================================================= 'Read remote temperatures from MODBus slave ' RTU address - AD“myDT80.com.au" ' Register 3 start address 1 - R3:1 ' Read consecutive registers to CV's - =1..2CV ' Read MODBus signed integers - MBI ' Integers have been x 100 so we x by 0.01 - 0.01 ' 3 re-tries - RT3 ' 15 second time out - TO15 4MODBUS(AD"myDT80.com.au",R3:1,=1..2CV,MBI,0.01,RT3,TO15,W) 1cv(ff2,"RmtTemp1~DegC") 'Remote Temperature 1 2cv(ff2,"RmtTemp2~DegC") 'Remote Temperature 2 End

DT80 Range Modbus applications Who use Modbus? Manufacturing Petrochemical Chemical Power Water Desalination Purification Waste treatment

DT80 Range Modbus applications What can we connect to? Programmable Logic Controllers (PLC) Controllers (Ovens, water baths, fridges, freezers etc) Human Machine Interfaces (HMI) Analog and digital I/O modules Smart Sensors RFID tag readers Pressure Supervisory Control And Data Acquisition (SCADA) Whole new ranges of sensors, devices and applications.

DT80 Range Modbus applications HMI Allows operator to enter data directly into DT80 Change set points Batch ID’s Operator ID Graphical display of real time data to operator Indicators Charts Mimic type displays.

DT80 Range Modbus applications Dam monitoring Multiple remote sites (50+) Mix of sensors SDI-12 Modbus depth sensor Vibrating wire piezometers Remote Network connection via VPN back to central SCADA system Data is backed up by using dataTaker unload commands to a separate system.

DT80 Range Modbus applications Vehicle location & down time monitoring In each vehicle Modbus RTU RFID tag read Touch screen HMI DT80 RFID tags distributed around site If a vehicle has been stationary for more than a set period of time then the driver is required to input a reason why.