Resolve UDP Port Warning: Unable to Read Any Data
Issue
These remedies apply when you receive no data and you get this warning message:
'udpport' unable to read any data
Possible Solutions
Try these remedies to resolve the following causes when you use the UDP interface for:
Reading ASCII (text) data using the
readline
function.Reading binary data using the
read
function.
Cause | Solution |
---|---|
An invalid command was sent to the destination UDP port, so there is a problem reading the response to the command. | Check the manual of the destination device for proper command formatting. |
An incorrect write terminator was sent to the destination UDP port before attempting to read data, so there is no data to read. | Verify that the Terminator property is set to
the value required by your destination UDP port. For more
information about setting the property, see configureTerminator . |
The destination UDP port did not receive the command because of an incorrect destination port value. | Verify that the UDP destination port value is set to the port
number the device is listening on. For more information about
setting the destination port, see write or writeline . |
A firewall is blocking incoming UDP packets. | Verify that your system firewall setting allows connections to
LocalPort . |
The UDP packet size is larger than the maximum packet size that can be handled by the Ethernet adaptor. | The UDP packet size is controlled by the
OutputDatagramSize property. You can specify
the size, in bytes, between 1 and 65507, and the default value is
512. |