How to Use UNI-T UT371 Count Mode for Object and Rotation Counting Malaysia
The UNI-T UT371 Non-Contact Tachometer is mainly used for RPM measurement, but it also includes a Count mode for accumulating detected movements or reflective targets.
The counting range is 0 to 99,999 counts. This function can support short-term machinery checks, component counting and repeated-movement observations when the target can be detected optically.
RPM Mode vs Count Mode
RPM mode and Count mode provide different results.
RPM mode calculates how many rotations occur per minute.
Count mode accumulates the total number of detected target movements.
For example, RPM mode may show that a shaft is rotating at 1,000 RPM, while Count mode records the number of times a reflective target passes the measuring point.
Possible Count Mode Applications
Depending on the target and measurement arrangement, Count mode may be used for:
Counting shaft rotations
Counting fan blade passages
Counting repeated machine movements
Counting reflective components
Short-term production checks
Verifying cycling mechanisms
Comparing machine output over a fixed period
Training and laboratory demonstrations
The target must be clearly detectable by the UT371 optical sensor.
How to Count Shaft Rotations
To count complete rotations:
Switch off and isolate the machine.
Wait for the shaft to stop.
Clean a suitable target area.
Attach one reflective marker.
Restore the required safety guards.
Select Count mode on the UT371.
Aim the instrument at the marker.
Start the machine according to the site procedure.
Stop the count when the required test period is complete.
Each detected reflective marker represents one complete rotation when only one marker is used.
Counting Fan Blade Passages
Count mode may be used to count blade passages if each blade can be detected clearly.
However, the result represents the number of blade passages, not the number of complete fan rotations.
For example, if a fan has four equally detected blades:
Four detected counts may represent one complete rotation
Forty detected counts may represent approximately ten rotations
The blade quantity and target arrangement must be considered when interpreting the result.
Counting Moving Objects
The UT371 may count objects when each item passes through a consistent optical detection point and produces a clear change in reflection or light.
Suitable conditions include:
Objects move one at a time
The spacing is sufficient for individual detection
The target position remains consistent
The object has adequate optical contrast
The tachometer can be held steadily
The detection path is not obstructed
This handheld function is intended for checking and observation. It is not a replacement for a permanently installed industrial production counter.
Avoid Double Counting
Double counting may occur when:
An object has multiple reflective surfaces
Two markers are attached to one rotating component
Polished metal produces additional reflections
The instrument moves during counting
The target passes through the detection area irregularly
Surrounding light interferes with the sensor
Use one clearly defined reflective target whenever each count must represent one event.
Avoid Missed Counts
Counts may be missed when:
The reflective marker is dirty
The target is too small
The measuring distance is unsuitable
The laser is not aligned with the target
The instrument is moving
The target is partially hidden
The object moves outside the detection area
Strong ambient light affects detection
Test the setup with a small known quantity before beginning a longer count.
Verify the Count with a Known Test
Before relying on the result:
Reset the count to zero.
Move or rotate the target a known number of times.
Compare the UT371 result with the known quantity.
Adjust the target position if the count does not match.
Repeat the test until the detection is consistent.
This verification is especially important when counting small or fast-moving targets.
Count Mode Limitations
The UT371 is a handheld optical instrument.
Its counting result depends on:
Target visibility
Reflective properties
Measuring distance
Instrument stability
Movement speed
Ambient lighting
Target spacing
It does not provide automated rejection, production control, alarm output or integration with factory control systems.
Applications requiring continuous industrial counting may need a dedicated photoelectric sensor and counter.
Safety During Counting
Never place reflective tape or adjust a target while machinery is operating.
Always:
Isolate the equipment before preparing the target
Disable automatic starting
Restore guards before operation
Maintain a safe distance from moving parts
Keep hands and clothing away from shafts and belts
Follow workplace machinery safety procedures
Avoid pointing the laser toward anyone’s eyes
Do not use Count mode if the target cannot be observed safely.
Is UNI-T UT371 Suitable for Your Counting Application?
The UT371 is suitable when a technician needs a portable instrument for temporary counting or rotation verification.
For continuous production counting, automatic monitoring or control-system integration, a permanently installed industrial sensor is generally more appropriate.
Contact MTM Precision with the target type, movement speed and required count method for assistance determining whether the UNI-T UT371 is suitable.
MTM Precision Sdn Bhd
Showroom & Service Centre: No. 29-1 & 29-2, Jalan Bandar 18, Pusat Bandar Puchong, 47160 Puchong, Selangor, Malaysia
Tel: 03-8080 7172
WhatsApp: +6016-660 7346
Email: mtmpre@yahoo.com
Website: www.mtmpre.com.my
30 Sep 2026
