Larcan Inc MXI1503U Manuale Utente
MXI1503-2004 OPERATIONS AND MAINTENANCE
PUB13-10 Rev 1
8
Usually in the application of AC, the modulator goes through its warm-up sequence and may take a few
seconds before it is ready.
seconds before it is ready.
2.
POWER METERING is at Zero.
On the LCD (see Main Menu display in Figure 6), the PWR should be at 000% and the STATUS should
be TX IS OFF, NORMALLY.
be TX IS OFF, NORMALLY.
3.
MAIN CONTROLLER is ready.
If there were prior faults, clear them by pushing the RESET button on the power supply chassis front
panel.
panel.
4.
INTERLOCKS are closed or OK.
Interlocks and Status are OK.
Figure 4 Interlocks Status
5.
The Amplifier is in LOCAL mode.
Push the REM button so that it is NOT lit.
6.
The TX is OFF.
Push the Front Panel ON/OFF button so that it is NOT pushed in.
5.4 A
MPLIFIER
ON
S
EQUENCE
Upon depressing the ON button, the fans start and at the same time the +50V power supply is enabled, thus
applying DC power to the amplifies. Since the modulator/up-converter or Channel Processor are on hot standby
(RF is always applied), the amplifiers will ramp up to 100% output power quickly. The reason there is a ramp up is
incase there is a problem with the output system resulting in a large reflection of power. As the amplifier ramps
up it will see the reflection and start cutting back. For first time installations, it is recommended that the level of
the modulator be set to minimum initially and then increase in steps until 100% power is attained. This is done so
that catastrophic failure is avoided. Keep in mind that in a newly installed transmitter that loose or bad
connections in the output, as an example, are possible particularly when the output system is not swept for proper
matching or VSWR. Hence, as the power is increased, by observing the combined, single amplifier, reflected, and
reject power metering one will be able to assess if everything is in proper order.
applying DC power to the amplifies. Since the modulator/up-converter or Channel Processor are on hot standby
(RF is always applied), the amplifiers will ramp up to 100% output power quickly. The reason there is a ramp up is
incase there is a problem with the output system resulting in a large reflection of power. As the amplifier ramps
up it will see the reflection and start cutting back. For first time installations, it is recommended that the level of
the modulator be set to minimum initially and then increase in steps until 100% power is attained. This is done so
that catastrophic failure is avoided. Keep in mind that in a newly installed transmitter that loose or bad
connections in the output, as an example, are possible particularly when the output system is not swept for proper
matching or VSWR. Hence, as the power is increased, by observing the combined, single amplifier, reflected, and
reject power metering one will be able to assess if everything is in proper order.
5.4.1 Turning ON the Transmitter
1. Enable amplifier LOCAL operation by pressing the REM touch button such that the REM legend is NOT lit.
Push the front panel ON button.
The Transmitter should now be ON (if you did not turn the output level of the modulator all the way down
before turning the transmitter on the unit will come up to 100% power. If the modulators output was
reduced the output power will be 0 the status message will read “TX IS ON WITH NO RF DRIVE”)
before turning the transmitter on the unit will come up to 100% power. If the modulators output was
reduced the output power will be 0 the status message will read “TX IS ON WITH NO RF DRIVE”)
Figure 5 Transmitter ON with Full Drive