Eaton MTL83*C Modbus Software Manual

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Eaton MTL83*C Modbus Software Manual Manual pdf 7 page image

3INM MTL83xC PC Modbus Rev 1DRAFT - 06 January 20193 BACKGROUND TO THE MTL838C3 1 The analog-input multiplexer systemThe MTL838C is an analog multiplexer receiver that is used with the MTL831Chazardous area millivolt input multiplexer transmitter. The status of up to 32 analoginputs may be communicated from the hazardous area to the safe area via a datahighway, comprised of a simple twisted pair - over distances up to 2000m.Each data highway must be protected by an MTL5553/5053 digital isolator whenthe inputs are located in a Zone 0,1 hazardous area. The MTL831C is typically usedwith thermocouple and RTD inputs and is intrinsically safe. It can be mounted in aZone 0,1 hazardous area and will accept 16 inputs. For systems that do not requireZone 0 or Zone 1 installation, the MTL5553/5053 can be eliminated.Up to two MTL831C transmitters can be combined on a single MTL838C receiverinput - up to a total of 32 analog inputs - as shown in Figure 1.Figure 1 - MTL838C/MTL831C System DiagramThe MTL838C acts as a Modbus slave It may be connected into any standardModbus network, with up to 31 MTL838C slaves on each network. If each unit hasits full complement of 32 analog inputs, the status of a total of 992 analog inputsmay be passed to a Modbus master using a single RS485 network.3 2 Configuring the MTL838CThe MTL838C must first be configured using software on a PC and the USBconnection. This configures things such as the slave address and communicationparameters. After the initial configuration, the MTL838C is ready to communicatewith the Modbus host. At this point, the remaining configuration may be done inone of two ways:• on-line via the Modbus link, direct from the host• off-line using the PC software and USB connectionUsing the PC software is required for initial configuration and recommended forfirst time configuration of the measuring channels.MTL831Ctransmitter 1MTL831Ctransmitter 2mVSensors can be in Zone 0MTL5553/5053isolator/PSUmVMTL838Creceiver PLCRS485RS48519-30VdcPowerPC(MTL 83xC Configurator Software)USB2x SPSTrelaycontactsDATA HIGHWAY (BUS)Up to 16 THC, RTD,and mV inputspotentiometerUp to 16 THC, RTD,and mV inputspotentiometerZone 0, 1 or 2Hazardous AreaSafe Area