Type 3 Faults lower power and do not turn the PA Power Supply
OFF. A fault indication indicates that the power output has been
decreased.
NOTE
“ON” and “OFF” refer to the PA Power Supply (+230 VDC,
+115 VDC and +60 VDC). The Low Voltage Supply, (+30
VDC, +22 VDC, +8 VDC, -22 VDC and -8 VDC), remains ON
whenever main AC power is present and Low Voltage Supply
circuit breakers CB1 and CB2 are ON.
Refer to Figure Q-2, simplified diagram of the RESET circuit
and RESET function, for the following description.
Q.4.8.1
Reset Circuit Inputs
The reset circuit clears fault indications on the ColorStat™
panel and remote fault indications whenever:
a. The RESET button on the ColorStat™ panel is pressed.
b. A remote “RESET” command is received from the Exter-
nal Interface.
c. A “+5B Reset” signal is generated by the +5B reset circuit
on the Controller.
Other Reset Circuit Inputs include:
a. INHIBIT RESET (during turn-on): An inverted “K1
START PULSE” from the Controller is logic LOW during
step-start, and prevents any indication from being “reset.”
b. CONTROLLER SUPPLY FAULT-L: When AC power is
first applied, the “Supply Fault-L” input holds “Reset B”
LOW to inhibit false triggering until after the 1 second
Supply Fault delay.
Fault indication latches all operate from the +5B supply, so that
any fault indications “latched” before a power failure will re-
main latched unless the “+5B Reset” circuit operates.
The RESET circuit also operates from the +5B back-up supply.
If the +5B voltage decreases, the “+5B Reset” will clear all fault
indications before latch operation becomes unreliable.
Q.4.8.2
Reset Circuit Outputs
The Reset Circuit has two outputs, “Reset A” and “Reset B.”
Both outputs are logic LOW during a reset, but the “Reset B”
LOW-to-HIGH transition is delayed slightly and occurs after the
“Reset A” LOW-to HIGH-transition. The two outputs function
as follows:
a. “Reset A” CLEARS all fault indication latches.
b. “Reset B” CLOCKS any fault which is still present into
the latches again when the RESET command is released.
Q.4.8.2.1
“Reset A” And “Reset B” Operation
When a RESET command is generated, “Reset A” goes LOW,
and clears all fault status indication latches. At the end of the
RESET command, “Reset A” goes HIGH. After approximately
60 nanoseconds “Reset B” goes HIGH. If the fault is still
present, the fault detection circuit output and one Retrigger Gate
input are still HIGH. When “Reset B” goes HIGH the Retrigger
Gate output also goes HIGH and triggers the latch again.
Q.4.8.3
Latch Outputs
The following description refers to Figure Q-3, “Latched Fault
Status Indications, Simplified Diagram.” Only the latch outputs
are shown in the figure.
During normal operation, the latch NOT-Q output is HIGH, and
is inverted to provide a logic LOW output to the External
Interface. The Q output is LOW when there is no latched fault,
and is inverted to a logic HIGH signal which illuminates the
GREEN section of the LED.
A LOW-to-HIGH TRANSITION at the CLOCK input from a
fault detection circuit causes the Q output to go HIGH and the
NOT-Q output to go LOW, illuminating the RED LED section
and turning off the green section. The “D” and “Preset” inputs
are held HIGH, through a resistor to +5 VDC.
Type 1, Type 2, and latched Type 3 FAULT indications can be
RESET by depressing the RESET button on the ColorStat™
panel or by providing a remote “Reset” command; the indica-
tions will then change from RED to GREEN if the fault has
cleared. If the fault is still present, the status indicator will
change to RED again when the RESET button is released or
when the remote “Reset” command ends.
EXCEPTIONS: DOOR INTERLOCK and EXTERNAL IN-
TERLOCK status indications clear as soon as the door is prop-
erly closed or the cause of the external interlock is corrected.
To summarize LATCH operation:
a. A LOW-to-HIGH TRANSITION at a latch CLOCK input
generates a RED FAULT indication.
b. A logic LOW at a latch CLEAR input resets the fault
indication GREEN.
Q.4.8.4
Retrigger Gate Operation
The output of the Retrigger gate is a LOW-to-HIGH transition
at the Latch CLOCK input when:
a. A FAULT is detected and “Reset B” is HIGH (there is no
“Reset B” in progress), OR
b. “Reset B” goes from LOW to HIGH while a fault is still
present (the fault detection circuit output is HIGH). Reset
B goes from LOW to HIGH:
1. At the end of a manually generated “Reset” pulse.
2. On initial application or re-application of AC power,
when the “Controller Supply Fault-L” logic signal
goes from LOW to HIGH.
If a “+5B Reset” is generated, there will be no voltage for the
fault detection circuits or for most other logic, and the fault
detection circuit outputs will all be LOW. The latches will be
cleared.
Q.5
Circuit Descriptions
Refer to the LED Board schematic, 839-7855-184, in the Draw-
ing Package and to simplified diagrams in this section, as noted.
Section Q - LED Board (A32)
Rev. R: 11-11-96
888-2297-002
Q-5
WARNING: Disconnect primary power prior to servicing.
