Setup guide

Chapter 2 System Objects
Object Reference Manual 3-56 www.Automationdirect.com
valid response. After it tries the number of Retry attempts specified, the
Modbus object generates an alarm and releases the communication port
back to the communications subsystem which then moves on to the next
device in the polling queue (if any). Refer to Chapter 3,
Serial
Communications
, in the
LookoutDirect Developer’s Manual
for more
information.
Receive timeout is the time delay Lookout
Direct
uses in waiting for a
response from a device before retrying the request.
Advanced Modbus Parameters
The Modbus driver attempts to block the reads and writes of coils, input
registers and holding registers into groups to maximize communication
efficiency. Through the Advanced Modbus Options dialog box, you can
control the maximum block sizes that the driver uses. In fact, if your device
does not support the default block sizes, you may have to specify smaller
blocks.
The Advanced… button invokes the Advanced Modbus Options dialog
box you can use to customize specific options within the Modbus protocol.