Varec 2920, Installation And Operation Manual, Page: 115 / 194

Varec, Inc. 105
Chapter 7
MODBUS
After the 2920 FTT is mounted and wired, it must be calibrated or configured to operate
efficiently and effectively. This chapter contains information about configuring the MODBUS
communication protocol, including the following:
• Setting the Unit Address
• Setting Communications Baud Rate and Parity
• Setting the MODBUS Register Map
• Setting the RTD Type
• Calibrate the transmitter level, including calibrating the level switches and
configuring outputs as outlined in "Configuration & Calibration — Level, Limits, and
Outputs".
Basic Parameters
The 2920 FTT requires the setting of several Basic Parameters to enable it to operate in your
particular environment. These parameters are:
• Unit Addr
• Baud Rate
• Parity
• Gauge
Type
• Encoder Direction
• RTD Type
• Register Map
All these parameters are located in the Basic Setup menu. The procedure below details the
steps to set the Unit Addr. and can be used to set other Basic parameters by substituting the
appropriate parameter name for Unit Addr. Of course, the number of times you press Minus
or Plus to access a parameter will be different.
For proper communications, the following parameters must match the setting of the host
system:
• Baud Rate, Lev Com Units, Temp Com Units