Entron EN1000 series, Инструкция по установке и эксплуатации

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The main isolation is provided by electro mechanical control relay contacts that are in series
with the solenoid valve voltage supply and the CONTACTOR firing circuitry. In a non
initiated state, the relay contacts are open and no output from these circuits are possible.
When the control is initiated by the physical closure of a normally open set of external
contacts (commonly a foot switch) across the initiation circuit, the relays are energized and
their contacts close and complete the circuits to the solenoid valve and the contactor. The
outputs are not actually energized, however, until the microprocessor reaches the point in
the sequence at which the valve or contactor outputs are to be activated.
There is no way to guarantee that any control circuit will be immune to component failure.
It is always necessary to take personal safety precautions when operating any machinery.
Through a "process output" system, the EN1000 Series of controls can be programmed so
that if the 20 volt energizing voltage for the isolation relays appears in the absence of an
initiation, or if the SCR contactor conducts current at any time other than when programmed,
an output voltage will appear at the valve #3 terminals. This voltage can be used to sound
an alarm or operate a shunt trip breaker to remove line voltage from the machine and the
control.
In addition to the relay contacts mentioned above, there are other levels of isolation. The
initiation signals first pass through a circuit comprised of optoisolators before being passed
to the input circuitry of the microprocessor. The valve outputs are further isolated by the use
of optically coupled triac (solid state) outputs and the weld pulses are isolated by a pulse
transformer.
NOTE
: Valve 3 (SV5/SV6) will not be isolated if jumper "B" is used on TS3. See Isolation
Circuit diagram on Figure 4.7.1.
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