Read Position

Usage

status = flex_read_pos(u8 boardID, u8 axis, u8 returnVector);

Purpose

Reads the position of an axis.

Parameters

Parameter Discussion

axis is the axis to read. Valid values are NIMC_AXIS1 through NIMC_AXIS30. On motion controllers that support fewer than thirty axes, reading non-existent axes returns error –70006 (NIMC_badResourceIDOrAxisError). Refer to Axes for axis resource IDs.

returnVector indicates the destination for the return data generated by this function. Available return vectors include return data to the host (0xFF), to a variable (0x01 through 0x78), to an indirect variable (0x81 through 0xF8), and return no data (0). Refer to Input and Return Vectors for more detailed information.

Note  The suffix _rtn on the function indicates that the data must be returned to the host. When this calling convention is used, no returnVector is required.

Using This Function

This function returns the instantaneous position of the specified axis. For servo axes, it returns the primary feedback position in counts. For open-loop stepper axes, it returns the number of steps generated. For closed-loop stepper axes, it converts the primary feedback position from counts to steps and then returns the value in steps. Closed-loop stepper axes require you to correctly load values of steps per revolution and counts per revolution to function correctly.

Note  For closed-loop axes, this function always returns the position of the primary feedback resource. Refer to the Read Vector Space Position function for an easy way to read up to three axis positions for a vector space in one call.

Note  Refer to Function Execution Times for benchmark timing information about your controller.