User's Manual Part 1

71
CONTROL AND DISPLAY BOARD SCH0239AR0
DESCRIPTION
SCH0239A is the Main Board of the Amplifier Control. It could be considered the core of the equipment.
This board is based on a powerful 16 bit microcontroller that runs an optimized ad-hoc firmware for the transmitter.
The firmware can be simply upgraded by means of RS232 (see the paragraph below for more details).
On the board a small DC/DC power supply is present that converts the +24Vdc input signal to +5Vdc output signal
used for almost all the integrated circuits.
The microcontroller gathers all the informations from AMs (by RS485 bus), antenna directional coupler, interlock
chain, fans and so on. It makes these informations available on the local interface (display and leds) and remote
(RS232, RS485 and TLM).
The analog inputs are conditioned in order to make a good monitoring of the RF powers, RMS and PEP type. The
input gain is variable by a trimmer and should be calibrated as explained below. The internal A/D converter of the
microcontroller makes the sampling and converts these signals into digital.
The LCD has a CCFL backlight that is fed by the inverter INV1 (see the component layout of the board).
All the other boards inside the AC are connected to the display board.
- Dip-switches
On the display board two series of dip-switches are present (see SW1 and SW2 on the component layout).
Switches on SW1 is not used. Switches on SW2 must be set in the following way:
1 Not Used
2 Not Used
3 Not Used
4OFF
5OFF
6ON
7ON
8ON
FIRMWARE UPDATE
The microcontroller is provided with a built-in Flash memory containing the firmware. The firmware can be
updated with a later version without removing the apparatus from the rack and/or replacing the chip.
To upgrade it, connect a PC to the RS232 socket on the front panel of the apparatus by means of a cable