Serial Terminal Emulators; Forbidden Operations; Safeguards - Hitachi EC702HP Operation Manual

1.4 kw uhf 8vsb-atsc transmitter
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Section 4 - Initial Activation (ATSC Transmitters)
B- Via USB with the Digital Exciter
The communication of the digital exciter via USB port, is only possible with the use of the software
GUI8001 (optional).

4.3.2 Serial terminal Emulators

The Power Drawer can be configured using the serial terminal emulators.

4.3.3 Forbidden operations

There are transmitter parameters which are configured at the factory, parameters defined on
the purchase of the transmitter, which are not available to change.
- Canal
- Equipment model
There are other parameters that are configured in the factory, but allow changes in their values
by using a password. The careful use of the password is to prevent unauthorized access that
can cause the appearance of a reflected power at the transmitter and consecutively decreasing
the value of the output power of the transmitter due to the protective action of the same.
- L.O. Null
- Frequency image adjustment

4.3.4 Safeguards

A – Potência refletida
If the incidence of reflected power at the transmitter due to any external or internal factor occurs,
this can be viewed on the measurement screen (MEASUREMENTS [2000]) by the software's
navigation Menu, in the digital display, according to instructions given in the Operation Section of
the Digital Control System.
If the value of the reflected power exceeds the value of 2%* of rated power, the control will
immediately signal this fact by lighting the LED current alarm on the front panel of the digital
exciter, will provide, on the current alarm screen, and this will trigger the routine protection against
reflected power. This will gradually decrease the value of the forward power until the amount of
power reflected returns to less than 2% of rated output. At this time, the software returns to
gradually increase the value of forward power, foreseeing the possible disappearance of the
reflected power. Thus, the equipment will be oscillating between increase and decrease of the
direct power around the power value that provides a reflected power of 2% of rated power,
always seeking the return to the rated power of equipment.
The 2% value to generate the reflected power alarm is fixed, ie the alarm will always occur when
the reflected power is 2% of the nominal power of the EQP.
Already the reflected value that will make the EQP reduce direct power is configurable from 2 to
5%. To change this value, go to Setup Menu-> Alarms Mask-> Reflected and change as needed.
* Approximately
Manual Rev. 0.0 - April 2016
4-10

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