AR 350AH1A, Руководство по эксплуатации и обслуживанию

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Model 350AH1A
Rev B 29
3.5 FAULT DETECTION CIRCUITS
This section describes the function and theory of the Model 350AH1A’s fault detection circuits. All fault-
signalling circuits are wired directly to the control panel for processing.
Detected fault signals are recorded in temporary (volatile) memory before the amplifier control circuits act to
protect the amplifier, sometimes resulting in RF inhibit or shut down. In some cases, inputs are read multiple
times to prevent a transient signal from causing an unwarranted action. Note that after a fault condition has
been invoked, the circuit breaker CB1 must be left on to keep the temporary memory active, so that all faults
can be manually recorded for diagnostic purposes. Faults may be recorded by the host system if the host
software is written to respond to fault conditions. Fault conditions may be queried at any time during normal
operation of the amplifier. When there are multiple faults, the display can be scrolled to view all of them.
3.5.1 Thermal Faults
The 350AH1A output module contains a thermal sensor switch. In the case of a thermal fault, the line will go
high. The control panel displays TH , and the main power supply will be inhibited to allow the module to cool
down.
3.5.2 Power Supply Faults
The main power supply is monitored internally. If the supply fails to produce DC voltage within its
specification, a logic signal will signal the fault board, resulting in an amplifier shut down. The power supply
faults and inhibit signals are routed to the Control Panel. The fault signal is a logic high (+5VDC) when all is
well, switching to a logic low if a fault occurs.
3.5.3 ALC Fault
An ALC fault is invoked whenever the DC and output current limit controls do not function, causing the RF
power to exceed one of the preset limits. The ALC fault is a logic low when invoked. The logic low from the
ALC board signals the digital control panel, which, in turn, disables the RF output by inhibiting the driver.
3.5.4 Interlocks
The Model 350AH1A has two interlocks that are wired to the rear panel Safety Interlock connector. The
interlocks are separate circuits, with different actions taken when invoked. Both interlocks require normally
closed external circuits to allow the amplifier to function.
3.5.4.1 Inhibit Interlock
For interlock applications where the amplifier is not required to shut down totally (AC Off), this interlock
circuit inhibits RF amplification by disabling the low level amplifier stages and forcing the amplifier into the
Standby condition. The inhibit interlock is wired to the rear panel Interlock connector pins 1 and 8. A closed
circuit from Interlock connector pin 1 to pin 8 is required for normal operation. Opening the connection will
inhibit the amplifier and display
INT
on the front panel. When the inhibit interlock has been opened, the
amplifier returns to the Standby condition, forcing the re-assertion of the RF ON command to return to
normal operation.