Magnetic Instrumentation 942B, Инструкция по эксплуатации

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The collector of Q308 feeds two circuits:
1. Q307 inverts the logic level on the collector of Q308. The collector of Q307 is used to
drive Q303 that makes up half of the two transistor “AND” circuit that enables a
magnetize condition. Q303 must be on, signifying the capacitor bank is not charging,
before the collector of Q302 will be allowed to go low upon the initiation of the
magnetize signal (
+
15V applied to Pin 17 of header connector). This assures that the
capacitor bank is at the correct voltage level and is not charging before allowing the
magnetize or discharge function to be processed.
2. Q308 also drives the circuit that provides the control signal to the Solid State Relay,
(providing primary power to the charging transformers) from Pin 7 of the header
connector. To enable a charge condition, ground (supply common) must be applied to
Pin 6 of the header connector, allowing the collector of Q311 to go low. A low level on
the collector of Q311 turns on Q313 allowing the
+
24V supply to be seen through R333
and D305 (jumper wire) to Pin 7 of header connector. When Q313 is off the -24V supply
through R334, R333, and D305 (jumper wire) creates a slightly negative potential at Pin 7
of header connector holding the Solid State Relay off. Q309 is used to drive an at-voltage
(ready to magnetize indicator or relay coil) signal. If ground (supply common) is applied
to Pin 8 of the header connector (emitter of Q309), and the -24V supply through a relay
coil or an indicator is applied to Pin 5 of header connector, this coil/indicator will be on
when Q313 is off.
Discharge Circuit :
Pin 17 of the header connector is used to initiate the discharge function. When the
+
15VDC supply is applied to Pin 17 of the header connector Q302 will be turned-on and
provided Q303 is on, (signifying the charge circuit is not-active), ground (supply
common) is seen at Pin 12 of header connector. Pin 12 of header connector is used to start
the discharge timing sequence.
When Pin 12 of the header connector goes low, 2 conditions have happened.
1. The capacitor bank has been charged to the preset voltage level and the
charge function is not currently active.
2.
A magnetize input signal has been provided.
At the same time Pin 12 of the header connector goes low, Q310 is turned on holding
Q313 (charging transistor) off, disabling the charge function. The 3-Timer Chain IC301,
IC302, IC303 is enabled by Pin 10 of header connector, (Ov on Pin 10 = Disable
+
15V
on Pin 10 = Enable), and triggered by Pin 19 of header connector (Ov = trigger).