Modbus Operation; Figure 41 - Mt100 Configuration Software Output Tab With Modbus Selected - FCI MT100 Installation, Operation And Maintenance Manual

OPERATION
External Control Group Switching (EGS)
This mode automatically changes the MT100 calibration group based on a 4-20 mA output current from another device fed into the MT100 4­
20 mA input port. Start the application. Click USB Connect on the home screen. Select the Configuration branch from the menu tree on the
window's left side. Select the Extended Op. Mode tab. Click Toggle System Mode. Enter user level password 2772 at the prompt. Verify that
instrument is in the service state with Setup showing in System Mode field. Click External Control Group Switching (EGS) radio button.
Select the Group Switch Setup tab. In the window's External Control Group Switching Setup field, specify a 4-20 mA input value in the
text box and its calibration group assignment via the associated Group drop-down list (define up to 5 points starting with the lowest value at
the bottom). These entries determine which calibration group is active as the 4-20 mA input current varies. The EGS setup field's Reset
button provides a quick way to clear out all programming entries (mA value/calibration group assignment).
Click Send to Device to send the EGS programming to the instrument. Return to normal operation by selecting the Extended Op. Mode
tab and clicking the Toggle System Mode button (observe that System Mode field shows Running).

Modbus Operation

The MT100 offers Modbus as one of its digital communication protocol, but unlike the other digital communication protocols Modbus only
offers set up and configuration for the totalizer variable.
The MT100 Modbus physical layer uses the asynchronous RS-485 serial port of the MT100. There is no high speed Modbus over
Ethernet. The MT100 offers the two basic traditional transmission serial interface modes: RTU and ASCII message coding.
The MT100 offers the process variable parameters (value) in floating point form, which are organized as single or double precision floating
point registers. These registers are the 4000 and the 5000 group registers, both of which are accessed using Modbus 03 and 04 function
codes. Refer to Table
Setting the MT100 for Modbus Operation
The MT100 Configuration Software application is used to select the instrument's digital communication protocol.
Connect the MT100 USB port to a USB port on the PC on which the MT100 configurator software is installed using the supplied USB cable.
Launch the MT100 Configurator (with the PC already running and connected to the MT100). Select Configuration branch from the menu
tree on the window's left side. Observe that the Output tab is selected. In the window's Digital Output Selection field, check whether or not
Modbus is shown for Digital Bus. If not, use the Digital Bus pulldown menu to select Modbus. Then click Send to Device to program the
MT100 (enter "2772" user password).
74
15, page 76, for an overview of the registers.
Figure 41 – MT100 Configuration Software Output Tab with Modbus Selected
MT100 Multipoint Flow Meter
Fluid Components International LLC