LTM-32

The leak tester with automated testing process is characterized by the following properties:

High sensitivity (1 Pascal)
Measurement with overpressure or with vacuum
Measuring ranges up to 20 bar
Digital display of the measurement result in mmWS, Pascal or Ncm³/min.
Digital display of the test pressure
Monitoring of the test pressure
Freely programmable limit values and cycle times
Signal lamps for sealing/rework/leaking
Serial interface (RS-232);
Option: RS-485, Profibus interface
Evaluation software (option)
19″ case

General

The LTM-31 is an intelligent, automatic, microprocessor-controlled leak tester (leak measuring device) for leak testing using the pressure drop/pressure rise method. It has all the functions that modern leak testers must have. No water or oil bath required. The measurement takes place quickly. The results are objective and are not influenced by human inattention or other errors. The measurement and test results are displayed numerically. The precise, numerical measurement data enables an accurate assessment of the quality and trend. Two limit values can be set. Conspicuous good/rework/not-good messages make evaluation and sorting easier. The device can be used in manual workstations or in automatic production. It can be controlled by PLC or PC. Profibus interface is possible. All measurement results can be read out and the adjustable parameters can be programmed via the interfaces.

Measuring principle

The test specimen is filled with compressed air. The filling pressure (pre-pressure) is slightly higher than the later measuring pressure so that filling and pressure can calm down more quickly. After the filling time has elapsed, the pressure is switched to the measuring pressure. Now there is a short break to calm the pressure conditions. The device then switches to the measuring phase. The air supply to the test specimen is blocked. The pressure is continuously measured with high resolution. The pressure difference between the pressure at the beginning and at the end of the measuring phase is determined. The pressure drop is the measure of the tightness of the test object. After the measurement is completed, the test specimen is automatically vented.

The device essentially consists of the following units:

Electronic measuring and control device with display, keyboard and serial interface
Pressure transducer
Pneumatic control (solenoid valves, etc.)
Pressure preparation devices (pressure regulators, filters).

Display: The device has a large, 2×16-digit, illuminated LCD text display. Programming the device is very easy thanks to the instructions in the text display. Measured values and several other information, such as time settings, setpoints, are displayed directly or can be read by switching. Functional information is displayed in plain text.

Keyboard: numeric keypad and function keys

Pressure regulator: The device has two built-in pressure regulators, separately for filling pressure and for test pressure.

Test pressure control: The test pressure is continuously monitored and displayed digitally.

Setting the parameters: filling, calibration and testing time, setpoints, limit values are set using buttons.

Time setting: The duration of all test phases is set numerically. The time is set with a resolution of 0.1 seconds.

Limit value setting: Setpoints and limit values of the test pressure can be set numerically with a resolution of 0.1%.

Messages: Good/bad messages, major errors / print-missing messages are displayed by conspicuous lamps. In order to avoid gross manufacturing errors, a separate message is issued in the event of a sequence of several reject results.

Program memory: 64 different test programs can be preset and easily called up as required.

Zero point correction: The zero point is checked automatically.

Counting test results: The number of pass messages and reject messages are counted and displayed. This means that there is a constant possibility of monitoring the number of tested and defective test items. The trend in quality can also be monitored. If several test items in succession are above the limit value, a special message is issued.
Temperature compensation is possible (option). Depending on the nature and size of the test specimen, different temperature compensation methods can be used.
After entering the volume, the pressure drop is converted into leak rate (Ncm3/min). Measuring units (mmWS, Pascal, mbar) can be selected.

Interfaces: The device has a serial interface (RS-232/V.24) and can also be programmed or controlled through this. The interface makes it possible to output the measurement results to a printer or transfer them to a computer for documentation, report creation, statistical evaluation, graphical representation of measurement curves, histograms and for solving other quality-related tasks.
Special software for the above purposes and other customer-specific tasks can be supplied as an option.
The device can be controlled by PLC. 8 inputs and outputs are available for communication.
Other interfaces, e.g. fieldbuses, are possible on request.
Programmable pressure control is possible using a proportional valve (option).

Technical data

Measuring method: pressure drop/rise measuring method
Measuring ranges: The device is available with different measuring ranges
Test pressure: -1…+1 bar; 0 … 0.3 bar;
0 … 1 bar; 0 … 3 bar;
0 … 10 bar; 0 … 20 bar.
Pressure drop: 0 … ±20000 Pa (±2000.0 mmWS, 200.00 mbar) or 0 … ±2000 Pa
Resolution: up to 0.1 Pascal
Version: 19″ housing, 3U
Display: 2 x 16-digit LCD display, character height 8 mm
Filling time: 0 … 99.9 sec.
Fine filling time: 0 … 99.9 seconds.
Alignment time: 0 … 99.9 seconds.
Measuring time: 0 … 99.9 seconds.
Venting time: 0 … 99.9 seconds.
Piece counter: total parts, good parts, rework 1 and 2, rejects
Error messages: Plain text message on the LCD display
Test programs: 64
Data output: RS 232C interface and e.g. PLC
Pressure supply: connection to pressure network (overpressure)
Power supply: 230V, 50/60Hz