Advantech BB-USR604, User Manual

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BB-USR604
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Timer settings from 1 to 255 msecs are available. The default value is 16 msec.
Select lower settings to correct response problems.
TIMEOUTS
The USB timeout is the maximum time in milliseconds that a USB request can remain outstanding. Minimum read
and write timeout values between 0 and 10000 msec can be selected.
The default values are 0 for both read and write timeouts.
MISCELLANEOUS OPTIONS
The following settings can be selected or deselected by clicking the appropriate checkbox:
Serial Enumerator
- The function of the serial enumerator is to detect a Plug-and-Play enabled device (such as a
serial mouse or serial modem) that is attached to the USB serial port.
Serial Printer
- If enabled, serial printer will disable timeouts to allow for long delays associated with paper
loading.
Cancel If Power Off
- The Cancel If Power Off option can be used to assist with problems encountered when going
into a hibernate or suspend condition. This will cancel any requests received by the driver when going into
hibernate or suspend.
Event On Surprise Removal
- The Event On Surprise Removal option is generally left unselected.
Set RTS On Close
- Selecting the Set RTS On Close option will set the RTS signal on closing the port.
Disable Modem Ctrl At Startup
- This option is used to control the modem control signals DTR and RTS at startup.
Devices that monitor these signals can enter the wrong state after an unplug-replug cycle on USB.
MODBUS BASICS
Modbus is an industrial data communications protocol that emerged in the mid-1970s and continues to be widely
used in current industrial systems. Originally designed to link terminals with Modicon PLCs, it is simple, easy to
learn and implement, and free to use. It quickly became a defacto standard in the industry and has been widely
implemented with successful results.
Modbus is a message-based master/slave protocol (also sometimes referred to as master/client) typically
implemented across serial communications links such as RS-232, RS-422 and RS-485. It supports asynchronous
point-to-point and multi-drop communications.