R.V.R. Elettronica HC4, User Manual

Page: 21 / 72

HC4
17 / 34 User Manual Rev. 1.0L - 01/04/02
In general, the reduction of the RF power generated by the exciter will reduce the
variable that casued the foldback intervention, so that a new stability point is
reached.
If any reason makes it impossible to reach a new stable point, the protection system
of the HC4 will react with its Shut off/Restart procedure.
5.3.8.2 Shut off/Restart
The second kind of reaction of the protection system consists in forcing the
transmitter in stand-by mode when one of the monitored variables surpasses its
maximum allowed value.
To put the transmitter in stand-by, the hybrid coupler disables the exciter’s RF
power emission using the interlock circuit, thus disabling the overall transmitter
RF power.
Depending on the kind of problem that caused the failure, after the transmitter has
been inhibited, it will either be reactivated after a fixed time interval, or only when
the impeding condition has been solved.
In the Alarm menu, the first kind of configuration is noted by X - (Y), wile the
second is indicated with Wait. The third possibility is that the configuration of the
sistem does not implement any protection based on a certain parameter: This
would be noted with Dis. (Disabled).
While the amplifier is temporarily shut off for an alarm, the yellow WAIT LED is lit,
and the cause of the intervention of the protection system is written on the display.
When the protection intervenes for a parameter of "cyclic" kind, a counter is
incremented (the value X in the alarm screen). If the value of the counter reaches
the maximum admitted value (Y), the amplifier is definitively switched off, and the
red LED "fault" on the front panel is lit.
The button ALARMS RESET gives the user the opportunity to interact with the
protection system. Its effect is different depending on the status the amplifier is
when the button is pushed:
• If the system is in stand-by, waiting for the cycle time to expire, or if it is definitively
off in FAULT state, pushing the ALARMS RESET button will immediately turn
the amplifier on and reset the alarm counters
• If the system is transmitting, but some alarm occurred before, so that the alarm
counters are not all at "0", pushing the ALARMS RESET button will have no
effect unless the button is pushed wile the user is reading the Alarm menu. In
this way it is made sure that the user doesn’t reset possible alarms without
knowing they happened
The alarm counters are reset by the system itself without the need for an external
intervention after half an hour of undisturbed (i.e. without alarms) working of the
hybrid coupler.