Heinzmann E-LES 30, Manual

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5 Gas Valves E-LES
KRONOS 20
23
5 Gas Valves E-LES
5.1 Structure and Operating Principle
The stepping motor drives a spindle with external thread. The teflon-coated aluminium pis-
ton with internal thread moves in line with the rotation of the spindle. The special thread-
ing prevents play between spindle and piston threads. The piston moves within a coated
bushing. This bushing features three exponentially shaped intake openings. This profile al-
lows a gas flow change linear to the stepping motor position. Due to this design, only the
forces of friction of the valve itself act on the piston. The shaft of the stepping motor is
sealed against gas leakage.
The control electronics of the stepping motor is mounted directly onto the gas valve and is
controlled by the KRONOS control unit with a special bit pattern via 2 digital outputs. This
type of control in principle allows the use of different HEINZMANN control units for dif-
ferent purposes.
Immediately after energizing the system or after a reset the stepping motor carries out a
reference run towards stop to determine the zero position. This may take up to 8 seconds,
depending on the system’s dimensions. The system is ready for operation only after the
reference run is completed.