Motion Run Hookup Diagnostics (MRHD)

Use the Motion Run Hookup Diagnostics (MRHD) instruction to command the motion module to run any one of three different diagnostics on the specified axis as selected by the Diagnostic Test. Currently diagnostics are available to test the motor/encoder hookup for a servo axis, the encoder hookup, and the encoder marker hookup. Commutation Test is also available but only on an AXIS_CIP_DRIVE axis. Only the motor/encoder diagnostic initiates motion on the axis. This action consists of a short move of a user Motor Encoder Test Increment. The move is initiated by roughly 1 Volt per second ramping level of the servo’s drive output. The result of executing the MRHD instruction is that the parameters, Test Status and Test Direction Forward are updated.

Available Languages

Ladder Diagram

Function Block

This instruction is not available in function block.

Structured Text

MRHD(Axis,MotionControl,DiagnosticTest);

Operands

There are data conversion rules for mixed data types within an instruction. See Data Conversion.

Ladder Diagram and Structured Text

See Structured Text Syntax for more information on the syntax of expressions within structured text.

For the operands that require you to select from available options, enter your selection as:

MOTION_INSTRUCTION Structure

Description - AXIS_SERVO, AXIS_SERVO_DRIVE

The MRHD instruction is used to execute various test diagnostics on the specified axis to test the integrity and, in some cases, the polarity of servo field connections. There are currently test diagnostics supporting drive hookup, encoder hookup, marker hookup and motion module OK contact hookup. Test for Commutation also available when using Axis_CIP_Drive. During some of these test processes the motion module generates output to the external drive to produce a small amount of motion. Measurements made during some of these hookup diagnostic tests are saved as output configuration parameters that also serve as input data for a subsequent MAHD (Motion Apply Hookup Diagnostic) instruction. MRHD requires only one explicit input parameter, Diagnostic Test. Enter or select the Diagnostic Test to run and the axis to test.

If the targeted axis does not appear in the list of available axes, the axis has not been configured for operation. Use the Tag Editor to create and configure a new axis.

The MRHD instruction uses axis configuration parameters as input and output. The input configuration parameters that MRHD uses are shown in this table.

The axis configuration parameters that MRHD generates as output depend on the specified Hookup Diagnostic.

Motor Encoder Hookup Test

If the Motor Encoder Test is selected, the motion module enables the external drive and generates a 1 Volt per second output ramp to the drive while monitoring the encoder feedback. When the axis has moved a distance greater than or equal to the configured Motor Encoder Test Increment, the test voltage is set back to zero and the drive disabled. The motion module then reports the direction of travel which is stored as one of these output parameters:

If due to improper hookup, or some other problem with the system, the axis feedback fails to detect that axis reaching the configured Motor Encoder Test Increment within 2 seconds, the servo sets the test voltage back to zero and disables the drive. The control reflects this condition through the Test Status axis output parameter. This usually indicates that either the cabling to the drive or the cabling to the encoder is incorrect. Running MRHD with the Encoder Hookup Test selected is an effective method of isolating the problem to the encoder or drive.

Encoder Hookup Test

If the Encoder Test is selected, the motion module does not generate any axis motion, but simply monitors axis encoder feedback. The axis can then be moved by hand or by some other independent drive actuator to generate motion. When the motion module detects that the axis has moved a distance greater than or equal to the configured Motor Encoder Test Increment, the test is complete. The motion module then reports the direction of travel as one of the following MRHD output parameters.

If due to improper hookup, or some other problem with the system, the axis feedback fails to detect the axis reaching the configured Motor Encoder Test Increment after moving the axis at least that distance, then abort the test using the MAS instruction and check the encoder wiring.

Marker Hookup Test

If the Marker Test is selected, the motion module does not generate any axis motion, but simply monitors axis encoder feedback. The axis can then be moved by hand or by some other independent drive actuator to generate motion. When the motion module detects a marker (Channel Z) pulse, the test is then complete. The motion module then reports success via the Test Status.

If due to improper hookup, or some other problem with the system, the axis feedback fails to detect that axis reaching the configured Motor Encoder Test Increment after moving the axis at least that distance, then abort the test using the MAS instruction and check the encoder wiring.

Test Status

Conditions may occur that make it impossible for the control to properly perform the test operation. When this is the case, the test process is automatically aborted and a test fault is reported and stored in the Test Status output parameter. It is also possible to manually abort a test process using a MAS instruction which results in a test fault reported by the Test Status parameter. Possible values for Test Status are shown in the table below:

To successfully execute a MRHD instruction running the Motor Encoder Test, the targeted axis must be configured as a Servo Axis Type and the axis must be in the Axis Ready state. For other tests this instruction executes properly on either a Servo or Feedback Only axis type. If any of these conditions are not met than the instruction errs.

Description - AXIS_CIP_DRIVE

The MRHD instruction is used to execute various test diagnostics on the specified CIP axis to test the integrity and, in some cases, the polarity of servo field connections. There are currently test diagnostics supporting drive hookup, encoder hookup, marker hookup and motor commutation hookup. During some of these test processes, the motion module generates output to the external drive to produce a small amount of motion. Measurements made during some of these hookup diagnostic tests are saved as output configuration parameters. MRHD requires only one explicit input parameter, Diagnostic Test. Enter or select the Diagnostic Test to run and the axis to test.

If the targeted axis does not appear in the list of available axes, the axis has not been configured for operation. Use the Tag Editor to create and configure a new axis.

The MRHD instruction uses the CIP axis configuration parameters as input and output. The input configuration parameters that the MRHD uses are shown in this table.

The CIP axis configuration parameters that MRHD generates as output depend on the specified Hookup Diagnostic.

Motor Encoder Hookup Test

The Motor Encoder Hookup test is selected, the motion module enables the external drive and generates a 1 Volt per second output ramp to the drive while monitoring the encoder feedback. When the axis has moved a distance greater than or equal to the configured Motor Encoder Test Increment, the test voltage is set back to zero and the drive is disabled. The motion module then reports the direction of travel that is stored as one of these output parameters.

If due to improper hookup, or some other problem with the system, the axis feedback fails to detect the axis reaching the configured Motor Encoder Test Increment within 2 seconds, the servo sets the test voltage back to zero and disables the drive. The control reflects this condition through the Test Status axis output parameter. This usually indicates that either the cabling to the drive or the cabling to the encoder is incorrect. Running MRHD with the Encoder Hookup Test selected is an effective method of isolating the problem to the encoder or drive.

Encoder Hookup Test

If the Encoder Test is selected, the motion module does not generate any axis motion, but simply monitors axis encoder feedback. The axis can then be moved by hand or by some other independent drive actuator to generate motion. When the motion module detects that the axis has moved a distance greater than or equal to the configured Motor Encoder Test Increment, the test is complete. The motion module then reports the direction of travel as one of these MRHD output parameters:

If due to improper hookup, or some other problem with the system, the axis feedback fails to detect the axis reaching the configured Motor Encoder Test Increment after moving the axis at least that distance, then abort the test using the MAS instruction and check the encoder wiring.

Marker Hookup Test

If the Marker Test is selected, the motion module does not generate any axis motion, but simply monitors axis encoder feedback. The axis can then be moved by hand or by some other independent drive actuator to generate motion. When the motion module detects a marker (Channel Z) pulse, the test is then complete. The motion module then reports success via the Test Status.

If due to improper hookup, or some other problem with the system, the axis feedback fails to detect that axis reaching the configured Motor Encoder Test Increment after moving the axis at least that distance, then abort the test using the MAS instruction and check the encoder wiring.

Commutation Test

The Commutation test only applies to PM motors. This test applies current to the motor to align the rotor and check for proper phasing of a UVW encoder or Hall sensor, if applicable. Finally, the test measures the commutation offset.

Test Status

This parameter returns the status of the last Run Hookup Test service on the targeted drive axis. Conditions may occur that make it impossible for the control to properly perform the test operation. When this is the case, the test process is automatically aborted and a test fault is reported and stored in the Hookup Test Status output parameter. Possible values for Test Status are shown in the table below:

In this transitional instruction, the relay ladder, toggle the Rung-condition-in from cleared to set each time the instruction should execute.

Affects Math Status Flags

No

Major/Minor Faults

None specific to this instruction. A major fault can occur if an uninitialized reference or a reference of incorrect type is passed to the Axis operand. See Common Attributes for operand-related faults.

Execution

Ladder Diagram

Structured Text

Error Codes

See Motion Error Codes (ERR) for Motion Instructions.

Extended Error Codes

Extended Error Codes provide additional instruction specific information for the Error Codes that are generic to many instructions. Motion Error Codes (ERR) for Motion Instructions. The following Extended Error codes help to pinpoint the problem when the MRHD instruction receives an error message.

Status Bits

MRHD Changes to Status Bits

Example 1

When the input conditions are true, the controller runs the encoder diagnostic test on Axis1.

Ladder Diagram

Neutral Text Representation for RLL

MRHD(Axis1, MRHD_1, Motor_Encoder);

Structured Text

MRHD(Axis1, MRHD_1, Motor_Encoder);

Example 2

When the input conditions are true, the controller runs the encoder diagnostic test on Axis1 through a reference to it.

Ladder Diagram

Neutral Text Representation for RLL

MRHD(Ref_Axis1, MRHD_1, Motor_Encoder);

Structured Text

MRHD(Ref_Axis1, MRHD_1, Motor_Encoder);