flex_read_dac_output_limit_status

NI-Motion Functions

flex_read_dac_output_limit_status

Device Compatibility

Device Compatibility
7330
N
7340
Y
7344
Y
7350
Y
7390
N
NI SoftMotion Controller for CANopen—Xenus
N
NI SoftMotion Controller for CANopen—Accelnet
N

Read DAC Output Limit Status

Usage

status = flex_read_dac_output_limit_status(u8 boardID, u8 returnVector);

Purpose

Reads the status of the DAC limits.

Parameters

Name Type Description
boardID u8 assigned by Measurement & Automation Explorer (MAX)
returnVector u8 destination for the return data

Parameter Discussion

returnVector contains the reverse limits and forward limits, which are returned in one onboard variable: 0000 000R RRRR RRR0 0000 000F FFFF FFF0.

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 positive and negative torque limit status of the DAC output. Independent DACs that are not mapped to axes do not have torque limits, so those DACs always return False.

A DAC torque limit status is True (1) when the DAC output is saturated at the corresponding limit. This information tells you that the motor is operating at its maximum torque, probably due to an excessively high value of acceleration or deceleration. It also can indicate excessive friction on the axis, a completely stalled motor, or some other system fault.

When an axis is active (not in the killed, motor off state), this function returns the instantaneous state of the torque limit circuits. If the axis trips out on following error (a typical occurrence when operating at the torque limits), the DAC limit status is latched so you can tell which limit, positive or negative, caused the following error trip. The status remains latched until the axis is activated again by a Start Motion, Stop Motion, or Blend Motion function.