Clavis Type 7 - User Manual

The CLAVIS Belt Frequency Meter Type 7 is a two-component system designed for measuring belt vibration frequency and calculating belt tension. It consists of a hand-held meter and a sensor connected via an electronic cable. The meter provides both visual and audible feedback to the operator.

Function Description:

The primary function of the CLAVIS Belt Frequency Meter is to detect the natural frequency of vibration of a belt strand. This frequency is then used to compute the belt tension in units of force (Newton or pounds-force), provided the operator inputs the belt mass and span length. The meter supports two types of sensors: an optical sensor and an acoustic sensor.

Optical Sensor (Section 3.3):

The optical sensor utilizes an invisible infrared beam to detect belt vibrations. An orange LED aiming beam, with a narrow angle, guides the sensor's positioning. For optimal signal detection, the sensor should be held perpendicular to the belt at the center of the span, at a distance of 9.5 mm (3/8 inch). However, usable readings can still be obtained with the sensor up to 50 mm (2 inches) away from the belt and/or tipped up to 45° from perpendicular, accommodating physical restrictions. Measurements can be taken from the edge of the belt, and the toothed side of a belt is equally acceptable as a target. The sensor LEDs should be kept clean with a dry cotton cloth; solvents should not be used.

Acoustic Sensor (Section 3.4):

The acoustic sensor employs a CLAVIS patented technique to detect belt vibration signals while minimizing ambient noise. This sensor is particularly effective for belts with poor vibration characteristics or very small vibration amplitudes. The "jaws" of the acoustic sensor should be positioned over the center of the belt, at mid-length of the belt span, ensuring they do not touch the belt to avoid reducing the vibration signal. A range of acoustic sensors is available for different belt widths, with the standard Type 3 sensor suitable for all automotive applications.

Meter Operation and Display (Sections 3.1, 3.2):

The meter features a keypad with several keys for operation:

ON/OFF: Switches the meter on or off. It automatically switches off after 3 minutes of idle time to conserve battery life. A battery check is performed upon power-on.
SPAN (m): Used to enter the belt span length in meters. Holding this key down while using the UP or DOWN keys sets the value. Releasing the key results in an audible beep, indicating acceptance. Pressing it alone displays the current setting.
MASS (kg/m): Used to enter the belt mass in kg/m. Similar to the SPAN key, holding it down and using UP or DOWN keys sets the value. Releasing it results in an audible beep. Pressing it alone displays the current setting.
UP (Hz/N): Has two functions: increases SPAN or MASS parameters when used in conjunction with those keys, and toggles between Hz and Newton measurement modes.
DOWN (Lbs): Has two functions: decreases SPAN or MASS parameters when used in conjunction with those keys, and toggles between Hz and pound measurement modes.
MEM 1, MEM 2, MEM 3: Memory keys to store and recall up to 3 sets of belt parameters (span and mass). To store parameters, enter them and then immediately press the desired MEM key. Two beeps confirm successful storage.

The display window shows measurement results and provides visual signals. Audible signals indicate operational steps:

One Beep: Input accepted (e.g., after releasing SPAN or MASS key), or measurement taken (when sensor is aimed at vibrating belt).
Two Beeps: Span or mass data stored to memory.
Four Beeps: Combined with "0000" N or "0000" lb display indicates Newton or Pound result is out of range. Also indicates low battery condition when combined with "zero" countdown after pressing "On" key.

Setup and Use (Section 4.0):

Plug the sensor head into the meter body, ensuring correct alignment without force.
Turn the unit on using the ON/OFF key.
Load span and mass data or recall previously loaded data from memory.
- To load span data: Hold down SPAN, use UP/DOWN to set the number, then release SPAN. A beep confirms acceptance.
- To load mass data: Hold down MASS, use UP/DOWN to set the number, then release MASS. A beep confirms acceptance.
- To save to memory: After releasing SPAN or MASS, immediately press MEM 1, MEM 2, or MEM 3. Two beeps confirm storage.
- To recall from memory: Press MEM 1, MEM 2, or MEM 3.
Aim the optical sensor at the center of the selected belt span (gap 10 to 50 mm) or place the acoustic sensor across the belt at mid-span, ensuring it doesn't touch the belt.
Tap or pluck the belt. The meter will beep once to indicate a measurement was taken.
The display window will show the frequency result.
Press UP (Hz/N) to toggle to Newton, or DOWN (Lbs) to toggle to pounds. Pressing the same key again returns to Hz display.
Re-adjust belt tension and repeat measurements until target tension is achieved.

Operating Tips (Section 5.0):

Take readings as close to the center of the selected span as practical.
Use the longest accessible belt span. Minimum usable span length is 20 times the belt tooth pitch for synchronous belts and 30 times the belt top width for V-belts. Short spans can lead to artificially high tension readings due to belt stiffness.
Orient the sensor head with its long edge parallel to the belt's center-line to minimize aiming errors.
For new installations, rotate the belt system by hand at least one full revolution to seat and normalize components.
If the top surface is inaccessible, aim the sensor at the edge or inside surface of the belt.
The meter will not read belts under extremely low tension; increase tension until a reading is obtained.
Take three successive readings to ensure consistency. If readings vary by more than 10%, reassess the measurement technique.
Multiple readings at different belt orientations can help identify drive component problems (e.g., belt shaft, poorly mounted sprocket/pulley, irregular pulley groove).
When tensioning multiple V-belts, use a single belt near the center of the array.
Note that significant span length changes during tensioning may require updating the span input for accurate tension calculations.

Meter Range (Section 6.0):

Measures belt vibration frequencies between 10 Hz and 600 Hz.
If frequency is below 10 Hz, it displays "10.00" briefly, then "000.0".
If frequency is above 600 Hz, it displays "600" briefly, then "000".
For multi-shaft drives, selecting a different belt span might enable valid measurements if the frequency is out of range.
Calculates belt tensions up to 9,990 N (2,200 lb). Out-of-range tension results are indicated by "0000" and four beeps.
Unusual high tensions should prompt a check of span and mass parameters and target value calculations. If correct, the drive may exceed the meter's capacity, requiring traditional tensioning methods.

Calibration (Section 7.0):

The meter uses a stable quartz crystal. A precision mechanical resonator (tuning fork) is included for a spot check at 250 Hz.
Acoustic Sensor Check: Tap the tuning fork, then hold it steadily between the sensor jaws. The meter should read 250 Hz.
Optical Sensor Check: Tap the tuning fork on a hard surface, then hold it steadily 10-15 mm in front of the optical sensor. The meter should read 250 Hz.
Results within ±1% are acceptable. No adjustment is possible. For greater variance, the meter should be returned for calibration.
Annual certification is available from the manufacturer (Integrated Display Systems Limited) to NAMAS/UKAS standards.

Technical Specifications (Section 8.0):

Measurement Range: 10 to 600 Hz
Measurement Accuracy: ±1 significant digit below 100 Hz, ±1% above 100 Hz
Belt Mass Input Range: 0.001 to 9.990 kg/m
Belt Span Input Range: 0.001 to 9.99 m
Maximum Belt Tension Display: 9,990 N (2,200 lb)
Environmental Conditions:
- Operating Temperature: +10 to +50 °C
- Shipment and Storage Temperature: -40 to +70 °C
- Protection Class: IP54
Sensor Optical:
- Type: Infrared optical
- IR Wavelength: 970 mm
- Visible Aiming Beam: Narrow angle orange LED
- Housing: Machined aluminum
- Cable Length: 1 m
Sensor Acoustic:
- Type: Twin transducer noise canceling
- Housing: Cast aluminum
- Cable Length: 1 m
Power Supply:
- Battery Type: 4 x AA (MN1500) Alkaline only
- Expected Life: 20 hrs (Optical sensor), 100 hrs (Acoustic sensor)
- Compartment Location: Back of meter
Optional Rechargeable Batteries:
- Battery Type: AA (1300 mAh minimum)
- Charger: 12 to 15V DC output
- Socket/Polarity: 3.5 mm positive center

Maintenance Features:

Battery Condition (Section 3.5): A battery check is performed automatically on power-on. Low battery is indicated visually (flashing zeros, counting down from four to one) and audibly (four beeps). Batteries should be replaced within 30 seconds of removal to prevent data loss from memory keys. Expected battery life is approximately 20 hours with the optical sensor and over 100 hours with the acoustic sensor.
Charging Batteries (Section 3.6): The meter is compatible with rechargeable batteries and a charging unit (IDS accessory). A 3.5 mm, positive center charging socket is located at the bottom of the meter. Do not charge with the sensor head attached or use the meter while charging. Charging current is internally limited to 100 mA, with a typical full charge time of 12-14 hours. The meter's software signals charging status with flashing zeros and four beeps.
Sensor Cleaning: Optical sensor LEDs should be kept clean with a dry cotton cloth; solvents are not to be used.
Warranty and Repair (Section 2.0, 7.2): A 12-month limited warranty covers defects in materials and workmanship, provided product registration is completed. The warranty is void if the device is opened. The meter can be returned to Integrated Display Systems Ltd (IDS) for repair, recalibration, or annual certification. Contact IDS for detailed costs and shipping procedures.

Theory of Operation (Appendix 1.0):

The meter operates on the principle that belt tension (T) is directly related to its natural frequency of vibration (f) by the formula: T = 4ml²f², where 'm' is mass per unit length, and 'l' is span length. The meter's integral calculator processes the detected vibration signal to determine the frequency and then computes the tension. It is suitable for all power transmission belts, regardless of type or construction.

Serial Communication (Section 3.7):

Each reading is transmitted via an RS232 serial port. The protocol is 9600 Baud Rate, 8 data bits, 1 stop bit, terminated by a 'CR' (Decimal 13). Output is through a 9-way 'D' type plug (Pin 5 common, Pin 3 Transmit). Handshaking is not employed.

Clavis Type 7 Specifications

General

Brand	Clavis
Model	Type 7
Category	Measuring Instruments
Language	English

Clavis Type 7 - User Manual

Table of Contents

Summary

General Safety Tips

Safety First

Prohibited Usage

Handling and Environmental Precautions

Device Description

System Components Overview

Optical Sensor Details

Acoustic Sensor Details

Quick Start Guide

Optical Sensor Quick Start

Acoustic Sensor Quick Start

Functions

Keypad Operations

Audio;Visual Display and Signals

Sensor Descriptions

Battery Condition Monitoring

Battery Charging Procedures

RS232 C Serial Communication

Setup and Operation

Initial Setup and Data Entry

Data Storage and Measurement

Operating Tips and Best Practices

Best Practices for Readings

Troubleshooting and Analysis

Meter Range and Limitations

Frequency and Tension Limits

Multi-Shaft System Considerations

Calibration and Certification

Spot Check Calibration Procedure

Annual Certification Services

Technical Specifications

Measurement and Environmental Specs

Sensor, Power, and Battery Specs

Formulae and Conversions

Conversion Factors and Formulas

Theory of Operation

Tension-Frequency Relationship

Sensing Technologies Used

Limited Warranty Information

Warranty Terms and Contact

Belt Tension and Weight Data

Timing Belt Specifications

Wrapped, V, Wedge, Banded Belt Data

Cogged Raw Edge V, Wedge, Banded Belt Data (Part 1)

Cogged Raw Edge V, Wedge, Banded Belt Data (Part 2)

Ribbed Belt Specifications