Honeywell 7800 Series Product Data page 32

7800 SERIESS7800A2142 4-Line LCD Keyboard Display Module
• Interface enable/disable option
• Slave address
• Baud rate (speed)
• Parity
• Endian order (for 32-bit registers)
Fig. 40. Modbus setup menu
The up and down arrow buttons are used to scroll down to the line of the parameter to
edit. Pressing the right arrow or OK button navigates to the parameter edit page (unless
a display login is required first). Pressing the left arrow button exits this page and returns
back to the Display menu.
The Modbus interface can be enabled or disabled by selecting the "Interface" line and
pressing the right arrow or OK button (see Fig. 41). When the interface is enabled the
RS-485 pins of the edge connector (terminals 1-3) accepts Modbus communication
requests as a Modbus slave. When the interface is disabled the RS-485 pins provide a
communication bus for other 7800 SERIES accessories (Refer to page 5 Wiring). The
current enable setting is displayed initially.
Fig. 41. Modbus interface setup
The up and down arrow buttons are used to scroll between the two options: "Enabled"
and "Disabled". To commit the change the right arrow button is used to tab to the "Yes"
command and the OK button is pressed to save the selected setting. If the setting should
not be saved, scroll down to the "No" command and press the OK button. In both cases
control returns back to the Modbus setup menu.
The Modbus slave address can be edited by selecting the "Address" line and pressing the
right arrow or OK button (see Fig. 42). Only Modbus messages directed to this address are
acknowledged and messages sent to other addresses are ignored by this display module.
An address range of 1-255 can be configured. The current address setting is displayed
when the page is initially entered.
Fig. 42. Modbus address setup
The up and down arrow buttons are used to increment/decrement the slave address digits
on the edit line. The right and left arrow buttons are used to tab between the address digit
positions and the save commands on the right, "Yes" and "No". When the input focus is on
the save commands the up and down arrow buttons scroll between "Yes" and "No". When
the address is set to the value desired the "Yes" command is selected and the OK button is
pressed to commit the change. If the user decides not to save the displayed address, the
"No" command is selected and the OK button is pressed. In both save command cases the
control returns back to the Modbus setup menu.
The Modbus baud rate (speed) can be edited by selecting the "Rate" line and pressing
the right arrow or OK button (see Fig. 43). The baud rate can be set to one of the following
speeds:
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