nimcReadEncoderData |
Read Encoder Data
Usage
status = nimcReadEncoderData(TnimcDeviceHandle deviceHandle, TnimcAxisHandle axisHandle, i32 index TnimcEncoderData attribute, TnimcData* data);
Purpose
Reads status and data from the selected encoder.
Parameters
| Name | Type | Description |
|---|---|---|
| deviceHandle | TnimcDeviceHandle | assigned by Measurement & Automation Explorer (MAX) |
| axisHandle | TnimcAxisHandle | axis to read encoder information from |
| index | i32 | encoder index |
| attribute | TnimcEncoderData | attribute to read |
| data | TnimcData* | the value for the attribute you are reading |
Parameter Discussion
axisHandle is the axis to read with this function. Valid values are 1 through 30. On motion controllers that support fewer than thirty axes, reading non-existent axes returns error 70006 (NIMC_badResourceIDOrAxisError).
index is the encoder index value. Valid value is 1 for the primary encoder.
attribute is the attribute to read. The following are valid attributes:
- TnimcEncoderDataPosition
- TnimcEncoderDataIndexPosition
- TnimcEncoderDataIndexCaptureOccurred
data is the value for the attribute you are reading in the following structure:
struct{
i32 longData;
u8 boolData;
f64 doubleData;
} TnimcData;
Based on the attribute, the correct member of TnimcData will be returned by the motion controller. The values of the other elements in the structure are undefined.
Read doubleData in the TnimcData structure to retrieve the encoder position or encoder index position.
Using This Function
Use this function to read status and data from the selected encoder.
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Caution If this function uses reflective memory, it should not be used for event checking. In this case, only use the information returned by this function for display purposes. Refer to Reflective Memory Functions for more information. |
For encoder position, this function returns the quadrature count value of the encoder mapped to the selected axis.
For encoder index position, this function returns the captured index position after a Find Index search.
Read boolData in the TnimcData structure to retrieve the encoder index capture status. A value of TnimcTrue indicates that the encoder index position capture occurred. A value of TnimcFalse indicates that the encoder index position was not captured.
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Note Refer to Function Execution Times for benchmark timing information about your controller. |