In the development of the teachable switch recently added to the range of Schmalz vacuum switches, great attention was paid to ease of use in practical applications.

On the basis of many years of experience in the design of vacuum systems, the software of the switch (Type VS-V-AV/AH-T-...- S) was programmed so that the user can set the switch by pressing a button only once!

Practical example with a "conventional" vacuum switch (with potentiometer):

Until now, a vacuum switch with potentiometer used for system monitoring had to be set as follows:

1. The vacuum generator is switched on and the workpiece is gripped (whereby the absolute vacuum value is usually unknown).

2. The switching point is first adjusted with the potentiometer to the current vacuum value. The switching point is thus equal to the maximum vacuum value which the system can achieve.

This also means that the vacuum switch generates the "part-present signal" only when the maximum possible vacuum value is reached.

3. In order to obtain a practical switching point, the potentiometer is usually then turned back by 1/4 to 1/2 of a turn. This lowers the switching point, but the actual value of the switching point is still unknown.

4. The vacuum switch is thus now set to a switching point which lies below the maximum achievable vacuum value. The switching point is commonly set to about 20 - 25% below the maximum possible value, a value at which the workpiece will be held safely! The handling system will thus start to move as soon as the object to be moved has been gripped securely.

Practical example with the new vacuum switch with teach button:

The entire procedure for setting the vacuum switch to a practical value is handled by the software stored within the new vacuum switch VS-V-AH/AV-T:

When the workpiece is securely gripped, the user sets the so-called "teach point" by pressing a button once.

The actual switching point of this new switch is then set automatically to a value which lies 20% below the teach-point value.

The "part present" signal is thus generated automatically at a practical vacuum value.

Additional hysteresis:

On the switch with the type extension –S, the hysteresis is also fixed at 2% of the full-scale value, i.e. 20 mbar.

If the vacuum reaches this value, the switch generates a signal to inform the system that a critical vacuum level has been reached.

Summary:

• The switching point and the hysteresis set themselves automatically to a practical        value, and the subsequent fine adjustment which is necessary with other vacuum   switches is unnecessary!
• The user can thus rely on "process reliability at the touch of a button"!