Clarify the zero-point reference and proximity-sensor logic for forward and reverse rotation of rotary tables. This document prevents confusion during service and function testing.
2. Applicable Models
Type
Controller
Representative Models
Rotation Method
A
IMC400
VHA, VHL
Servo Rotation
B
IMC700 / IMC710
VHG5
Servo Rotation
3. Zero-Point Reference
Model
Zero-Point Position
Controller Logic Reference
VHA / VHL (IMC400)
Reverse-rotation completion position
Set ZRO (0°) at reverse-rotation completion
VHG5 (IMC700/710)
Forward-rotation completion position
Set ZRO (0°) at forward-rotation completion
4. Proximity Sensor Logic
Item
VHA/VHL (IMC400)
VHG5 (IMC700/710)
Remarks
Forward rotation complete sensor
Signal ON (1) = complete
Signal OFF (0) = complete
Logic inverted
Reverse rotation complete sensor
Signal ON (1) = complete
Signal OFF (0) = complete
Logic inverted
During rotation (intermediate)
Both sensors = OFF
Both sensors = ON
Signal inversion
Reference direction
Reverse-rotation completion
Forward-rotation completion
Controller difference
5. Checklist for Functional Test
Inspection Item
VHA/VHL (IMC400)
VHG5 (IMC700/710)
Evaluation Criteria
Forward/Reverse operation
Normal rotation in both directions
Same
Verify signal at completion
Proximity sensor operation
Sensor ON at completion
Sensor ON during rotation
Check sensor status
Zero-point confirmation
Reverse-rotation completion position
Forward-rotation completion position
Display = 0°
Position restore after restart
Normal
Normal
Zero maintained after power re-apply
6. Service Notes
Model Identification
IMC400 and IMC700/710 use different rotation logic. Confirm controller version first.
Sensor Reuse Caution
For logic-inverted models (VHG5), set sensor ON/OFF input as reversed.
Software Parameter
Do not change the Zero reference within the standard control logic.
If Zero Mismatch Occurs During Test
Check sensor input (IO monitor) → rotation direction → controller version in order.
7. Summary
VHA/VHL (IMC400): Zero = Reverse-rotation complete, Sensor = Completion state
VHG5 (IMC700/710): Zero = Forward-rotation complete, Sensor = During rotation → Because the logic is inverted, confirm the model-specific reference before all function tests and service operations.
