query_io_device — Query information about channels of the specified I/O device.
The operator query_io_device returns information about transmission channels of a specified I/O device. The handle to the I/O device is passed to in IODeviceHandle, whereas the channels are addressed by IOChannelName. The desired information about the I/O channels is specified via Query. A list of all supported channel names is usually returned when passing 'io_channel_name' to Query while the input parameter IOChannelName is ignored.
Please check the directory 'doc/html/reference/io' for documentation about your specific I/O device interface, where all supported channel-specific parameters are listed.
Handle of the opened I/O device.
Channel names to query.
Name of the query.
Default value: 'param_name'
List of values: 'io_channel_names', 'param_name'
List of values (according to Query).
query_io_interface ('Advantech', 'io_device_name', DeviceNames) open_io_device ('Advantech', DeviceNames, , , IODeviceHandle) query_io_device (IODeviceHandle, , 'io_channel_names.digital_input', ChannelInputNames) open_io_channel (IODeviceHandle, ChannelInputNames, , , IOChannelHandle) read_io_channel (IOChannelHandle, Value, Status)
If the parameters are valid, the operator query_io_device returns the value 2 (H_MSG_TRUE). If necessary an exception is raised. In this case, an extended error information may be set and can be queried with the operator get_extended_error_info.