Motion Run Hookup Diagnostics (Mrhd); Rockwell Automation Publication Motion-Rm002H-En-P-February - Allen-Bradley 1756 ControlLogix Instruction Manual

Chapter 5 Motion Configuration Instructions
Motion Run Hookup Diagnostics
(MRHD)
330
This information applies to the CompactLogix 5370, ControlLogix 5570,
Compact GuardLogix 5370, GuardLogix 5570, Compact GuardLogix 5380,
CompactLogix 5380, CompactLogix 5480, ControlLogix 5580, and GuardLogix
5580 controllers. Controller differences are noted where applicable.
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.
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.

Rockwell Automation Publication MOTION-RM002H-EN-P-February 2018

Only the motor/encoder diagnostic initiates motion