Physical Channel Syntax
Use this syntax to refer to physical channels and groups of physical channels in NI-DAQmx.
Physical Channel Names
Physical channel names consist of a device identifier and a slash (/) followed by a channel identifier. For example, if the physical channel is Dev0/ai1, the device identifier is Dev0, and the channel identifier is ai1. MAX assigns device identifiers to devices in the order they are installed in the system, such as Dev0 and Dev1. You also can assign arbitrary device identifiers with MAX.
For analog I/O and counter I/O, channel identifiers combine the type of the channel, such as analog input (ai), analog output (ao), and counter (ctr), with a channel number such as the following:
ai1
ctr0
For digital I/O, channel identifiers specify a port, which includes all lines within a port:
port0
Or, the channel identifier can specify a line within a port:
port0/line1
All lines have a unique identifier. Therefore, you can use lines without specifying which port they belong to. For example, line31—is equivalent to port3/line7 on a device with four 8-bit ports.
Physical Channel Ranges
To specify a range of physical channels, use a colon between two channel numbers or two physical channel names:
Dev0/ai0:4
Dev0/ai0:Dev0/ai4
For digital I/O, you can specify a range of ports with a colon between two port numbers:
Dev0/port0:1
You also can specify a range of lines:
Dev0/port0/line0:4
Dev0/line0:31
You can specify channel ranges in reverse order:
Dev0/ai4:0
Dev0/ai4:Dev0/ai0
Dev0/port1/line3:0
Physical Channel Lists
Use commas to separate physical channel names and ranges in a list as follows:
Dev0/ai0, Dev0/ai3:6
Dev0/port0, Dev0/port1/line0:2
See Also
Device-Specific Physical Channels