Modbus RTU Advanced Properties

Fields in the Advanced dialog box are as follows:

Advanced Settings


Click to update all fields with their default settings.



Click to define custom values for fields on this tab.

Timeout (sec)

Number of seconds the device communication will wait for a response to a poll request before declaring a read failure.

Read Delay (ticks)

The amount of time to wait for a response after issuing a request to the device.


Domain Type

Write Function

Register Write Function



Force Single Coil




Force Multiple Coils




Force Single Holding Register.




Preset Multiple Holding Registers.

Word Reverse

This affects four byte values only (REAL, DINT, UDINT). Some devices store the LOW WORD and HIGH WORD in reverse order (from a Modicon PLC). This will reverse them so they are displayed correctly in CIMPLICITY.

Cache Disable

By default, CIMPLICITY caches continuous addresses into a cache group. It then performs a single read on the group. Some devices will not allow this kind of group read. When caching is disabled, each point is read individually from the device. Note that in projects with large point counts, this can significantly affect performance.


Saves the values in the file \\site_root:data\master_port.ini, which is then read by the device communication interface the next time it is started.


Closes the device dialog box without any modification.

More information

MB_COMM_TIMEOUT Device Parameter.

MODBUS RTU Device Properties.

Modbus RTU device configuration.