Instruction manual

MODBUS System Set Up
26 025-9209
CONFIGURING THE 1700 CONTROLLER
When using the MODBUS option, the Model 1700 controller address is usually set to “1”
(DIP switch 1 ON, DIP switches 2 through 6 OFF). Any address in the range of “1” to “63”
could be used. It should never be set to “0”.
ii
The Model 1700 controller has built-in configuration menus that can be accessed through a
PC with a terminal program. For more information on the general configuration of a
controller, please see the “PROGRAMMABLE FEATURES” subsection of the “Model 1700
Controller Installation and Operation” manual, part number 025-9209. Only the menu items
that apply to the MODBUS option are discussed here.
MODBUS Menu
When the MODBUS option is installed in the controller, the main menu displayed contains
an additional item right after the RS232 {W}atchdog item, {M}odbus. Typing an “m” will open
the menu listed in Table 12.
Table 12. 1700 Controller MODBUS Menu
Menu Selections Range Factory Settings
{R}TU status storage Enable, Disable Enabled
{A}utopoll...
Autopoll interval
(0 to 65535 minutes)
First autopoll RTU
(1 to 255)
Number of RTUs
(1 to 255)
Autopoll interval = 0
First RTU = 1
Number of RTUs = 1
E{x}it
The following two subsections make reference to the items on the MODBUS menu.
Polled-Only Configuration
For a MODBUS, polled-only system, you must configure the following items. This is in
addition to any other parameters you configure on the controller.
1. From the controller main menu, type “M” to open the MODBUS menu.
2. From the MODBUS menu, type “R” to open the RTU Status Storage item.
3. At the RTU Status Storage prompt, type “D” to disable the status storage feature. This
should return you to the MODBUS menu.
ii
The address “0” is a reserved address in the MODBUS protocol. If you give a controller or RTU an address of
“0”, the PC or PLC will not be able to communicate with it.