G4 Multi Channel Weighing Instrument. PM/DT/HE Technical Manual

G4 Multi Channel Weighing InstrumentFieldbus interfaceThe optional fieldbus interface is based on a network communication module fromHMS Industrial Networks. Available fieldbusses are Profibus and DeviceNet. Withsetup parameters the fieldbus interface is configured for the specific needs of aninstallation. It is possible to setup address, baud rate (if applicable to the actual fieldbustype) and mapping of the memory area in the fieldbus module that is available to thenetwork.The mapping is divided in one base block for data from the master to the instrument,one base block for data to the master from the instrument and 0 – 12 (selected with asetup parameter) configurable data blocks. The base blocks are mandatory. The datablocks are configurable regarding the content and in some cases also format (floatingpointor integer).The registers mentioned below are Modbus registers as defined in sectionCommunication – Modbus Protocol. Each Modbus register is two bytes wide. Thissection also describes commands.The size of the base blocks is 16 bytes from master to instrument and 32 bytes fromthe instrument to the master. The base blocks contain Instrument Error and InstrumentStatus. Besides instrument error and status information are the base blocks used forgeneral purpose reading and writing of data and also for issuing commands to theinstrument.The mapping in the master and the instrument must always correspond.Setup of fieldbus communication• Complete the set-up of fieldbus communication before connecting it to the networkto avoid possible network failure due to mismatch in configuration between networkand instrument.• Select the fieldbus type used in the ‘Hardware Configuration’ menu.Note that the instrument will be restarted after changes in the hardware setup.• Select the appropriate device address for the instrument. Address is setup in menu‘Communication – Fieldbus’.Note that the address range is depending on type of fieldbus.• Select baudrate, if applicable, according to the used baudrate in the network. Somefieldbusses may support automatic baud rate setting. Use fixed baudrate setting ifthere are difficulties to connect to the network or if the network baudrate is known.• Select the number of data blocks that is needed for the installation. It is possible touse only the “base block” mapping if there is room for all necessary data within the12 consecutive modbus registers that are defined within the base block (data fromthe instrument). The starting address of the read area is settable.• Configure the desired number of data blocks. Note that the data blocks may still beconfigured as ‘Not In Use’ in which case the data within the block will be undefined.• Check that the configuration of the master is compatible with the actualconfiguration of the instrument.• Connect to the network.6-29