C h a p t e r 3 F u n c t i o n G u i d e
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3.3.4 MODBUS cache table
Since the transmission speed of Ethernet interface is faster than that of serial ports, therefore, when Ethernet
devices send requests to serial devices, more time is required for waiting serial port data. MODBUS cache
table provides PLCs with relevant configuration information (e.g. station ID, MODBUS IP). The DVW device
can send request to receive serial port device data based on prior MODBUS cache table. When Ethernet
devices requests for transmission to DVW device, DVW can immediately respond to data. Because DVW has
already receive the data in advance, so it does not need to transfer the requests to serial devices and the
function can also be used in MODBUS ASCII/RTU slave mode.
3.3.4.1 RS-485 cache table
On the left part of the cache table page displays information regarding configuration; click
Online
and data
read based on configuration messages are shown on the right.
Explanation
Default value
Enabled
Set MODBUS cache function to enable or not enable.
Not checked
Cycle time
Set the time for sending requests to serial devices.
1000
Available size
Displays the available data size for monitoing.
Timeout calibration
Calibrate the response timeout. When users click
Detect
, the DVW
device will use the MODBUS cache table for communication.
