M Series Physical Channels

In physical channel names, Dev1 is the default device name for M Series devices. You can change these names in MAX.

Analog Input

Depending on your M Series device, you can have from 16 to 80 analog input channels. A 16-channel M Series device has physical channels ranging from Dev1/ai0 to Dev1/ai15, a 32-channel device from Dev1/ai0 to Dev1/ai31, and so on. You can configure the first eight channels as the positive channel of a differential pair. If N is this channel, channel N + 8 is the negative input of the pair. For instance, if you configure channel 1 in differential mode, the positive input is channel 1, and channel 9 is the negative input. For devices with more than 16 AI channels, 16-23, 32-39, 48-55, and 64-71 are also positive channels of a differential pair.

Use only the physical channel name of the positive channel (not both) when creating a differential channel.

Analog Output

An M Series device that supports two analog outputs has analog output physical channels named Dev1/ao0 and Dev1/ao1.

An M Series device that supports four analog outputs has analog output physical channels named Dev1/ao0, Dev1/ao1, Dev1/ao2, and Dev1/ao3.

Digital Input and Output

All M Series devices have eight, 16, or 32 lines of digital input and output named Dev1/port0/line0 through Dev1/port0/line7, Dev1/port0/line0 through Dev1/port0/line15, or Dev1/port0/line0 through Dev1/port0/line31. These lines belong to a single port, and the physical channel Dev1/port0 refers to all eight or 32 lines at once. Port 0 can perform both hardware-timed and static digital operations.

M Series devices have two more ports, port 1 and port 2. Port 1 has eight digital I/O lines, Dev1/port1/line0 through Dev1/port1/line7. Port 2 has eight digital I/O lines, Dev1/port2/line0 through Dev1/port2/line7. Port 1 and port 2 can be used as static digital I/O lines or PFI lines, PFI 0..15. When any of PFI lines 0..15 is used as a digital I/O signal, it uses the physical channel name shown in the following table.

Physical channel Dev1/port1 refers to all eight lines, Dev1/port1/line0:7, at once. Physical channel Dev1/port2 refers to all eight lines, Dev1/port2/line0:7, at once.

Counter Input and Output

All M Series devices have two counter/timers referred to by the physical channel names Dev1/ctr0 and Dev1/ctr1. Unlike the other I/O types, these physical channel names do not refer to terminals on the I/O connector but instead to circuits within the device. There are four primary terminals associated with each counter. These are the terminals used as the SOURCE, GATE, AUX, and OUT functions. NI-DAQmx has default values for these terminals. For counter input tasks, if you know whether your signal provides the SOURCE, AUX, or GATE function and wire your signal to the default, you do not have to set the Input Terminal attribute/property.

Refer to M Series Signal Connections for Counters for more information.