29
JMNC Operating Instructions
6 Setting the Rotational Speed Monitoring Device JMNC
5
Setting the nominal value of the switch point
Very slowly turn the potentiometer Coarse (
6
)
(nominal value setting) counter-clockwise, until…
Observe the pulse intervals
The switch points cannot be set during the pulse
intermissions.
… the green LED (
5
) lights.
Now the switch point is roughly adjusted to
the operating rotational speed.
When the pulse selection switch (
2
) was set
to position I (8 … 120 Imp./min.), long pulse
intermissions can be caused by low speeds,
e. g. 7.5 s at 120 pulses/min.
6
Slowly turn the potentiometer Coarse (
6
)
clockwise, until …
… the green LED (
5
) extinguishes.
7
Precise setting of the switch point
Slowly turn the potentiometer Fine (
3
) counter-
clockwise, until …
… the green LED (
5
) lights. If the green LED
(
5
) does not light, though the potentiometer
Fine (
3
) was turned up to the stroke, turn the
potentiometer Fine (
3
) completely back, and
repeat the setting, starting with item 5.
The switch point of the output relay (
16
) is
now set precisely to the operating speed.
For devices without activated run-up bridg-
ing, the output relay (
16
) is attracted when
the drive reaches this rotational speed.
8
Switch-off point at 10% underspeed
Due to the switching hysteresis, the switch-off
point is approx. 10% lower than the switch-on
point,
i. e. when the operating rotational speed is
reduced about 10%, the output relay (
16
)
drops.
Item
Description
Indication/Action
Fine
±10%
