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BTM-400PLUS Belt Tension Meter (Trummeter)

Made in Germany
BTM-400PLUS Belt Tension Meter
Click images to enlarge.
Supplied with plug-in and cable-connected sensors

The CHECKLINE BTM-400PLUS accurately measures the static tension of flat, V and ribbed belts of rubber, leather, fabric and composite materials by measuring the natural frequency (Hz) of a segment of the belt that has been tapped and then converting it into tension units of newtons (N) or pounds force (lbf).

The instrument uses a pulsed ruby-red light source to measure the natural frequency of the vibrating belt. Unlike competitive models, the BTM-400PLUS is NOT affected by ambient noise, providing quick reliable results in all production and field applications.

Similar to SKF PHL FM 10/400


  • Includes two (2) separate Sensors – a plug-in type for one-handed operation and a cable-connected type for measuring belts with limited access space
  • Compact, easy-to-use design
  • Readings unaffected by nearby magnetic fields or noise
  • Displays tension in newtons (N) or pounds force (lbf) or natural frequency in Hertz (Hz) - selectable
  • Displays Menu in English, German, Spanish, Portuguese, French or Italian & others - selectable
  • NIST and ISO-17025 Traceable Calibration Certificate - OPTIONAL

External Probe Dimensions

probe dimensions

Complete Kit

The BTM-400PLUS is supplied as a complete kit, including: the gauge, plug-in and cable connected sensors, 9-volt battery, Instruction Manual all in a foam-fitted, hard plastic carrying case.


Measuring Range*10 - 800 Hz
Indicator error±1 Hz
Total error< 5 %
Sensing Distance***0.200" - 1.6" (5 - 40 mm), typically (2.5"/60 mm max, depending upon ambient light & surface of belt to be measured)
CasingABS Plastic
Display2 line LCD, 16 character per line
Input Rangefree span length: up to 9.990 m
belt mass: up to 9.999 kg/m
Belt DensityBelt Density (d = kg/m or lb/ft)
Belt SpanMin, approx. 10 cm (4 inch)
Max, no maximum (as long as belt will oscillate)
Warranty1 Year
Light SourceRed LED
Light Sizeat 50mm - 6mm Square
at 150mm - 15mm Square
Power Supply9V battery
Metric UnitsMASS must be entered in kg/meter
SPAN in "meters"
English UnitsMASS must be entered in lbs/ft
SPAN in "inches"
Operation Videohttps://www.youtube.com/watch?v=-l4-uG0JIAc&feature=youtu.be
Country of OriginGermany
*BTM-400PLUS can measure up to 800 Hz, however most belts will break near 400Hz

**Static tension (T) accuracy depends on the precision of entered values for free belt span (L), density (d) and natural frequency (f) of the vibrating free belt span, that has been plucked or struck, as noted in the relationship: T = 4dL2f2. Note that highest accuracy is achieved in the frequency mode where readings are accurate to <1%, ± 1 Hz.

***Sensing distance can be extended when ambient light level is low also by adding a piece of reflective tape in the "target area" of the belt.


Buy Now

Item Description Price
Belt Tension Meter, Measuring Range: 10 - 800 Hz
NIST Traceable Calibration Certificate
ISO-17025 Calibration Certification & Report for BTM Belt Tension Meter
Spare LED Plug-In Sensor for BTM-400PLUS
Spare Cable-Type Sensor for BTM-400PLUS
Reference Tuning Fork set, 128 and 256hz, without certification
10 Strips of 1/2 x 4 inch reflective tape
5" / 125 mm long Gooseneck flexible sensor for BTM-400PLUS
10" / 270 mm long Gooseneck flexible sensor for BTM-400PLUS
In stock
1 Week Lead Time (Estimated)
2-3 Week Lead Time (Estimated)
Lead Time Varies, Please contact us for availability.