imaqIORead
Format
rval = imaqIORead(IMAQIO_SESSION id, IMAQIOSignalType signalType, unsigned long signalNumber, IMAQIOSignalState* value);
Purpose
Reads general-purpose digital inputs from the static I/O of the NI-IMAQ I/O device.
Parameters
| Name | Type | Direction |
| id | IMAQIO_SESSION | input |
| signalType | IMAQIOSignalType | input |
| signalNumber | unsigned long | input |
| value | IMAQIOSignalState* | output |
Parameter Discussion
id is the ID of the session to read from.
signalType is the type of signal to read from. The following values are valid for this parameter:
| Name | Constant | Description |
| IMAQIO_SIGNAL_ISO_IN | 2 | ISO input signals include pulse trigger inputs, a shutdown input, and a quadrature encoder input. |
| IMAQIO_SIGNAL_ISO_OUT | 3 | ISO output signals are general-purpose outputs. |
| IMAQIO_SIGNAL_TTL_IN | 5 | TTL input signals are general-purpose inputs and pulse trigger inputs. |
| IMAQIO_SIGNAL_TTL_OUT | 6 | TTL output signals are general-purpose outputs and pulse generation outputs. |
signalNumber is the line number of the signal to read from.
value is a pointer to the signal state read from the NI-IMAQ I/O device. The following values are valid:
| IMAQIO_SIGNAL_STATE_HIGH | Drives the line high when the signal is TRUE. |
| IMAQIO_SIGNAL_STATE_LOW | Drives the line low when the signal is TRUE. |
| IMAQIO_SIGNAL_STATE_HI_Z | Disables output on the line. This option is valid only for TTL Outs. |
Return Value
This function returns 0 on success. On failure, this function returns an error code. For information about the error code, call imaqIOGetErrorText.