Has anyone any experience in controlling a high power amp with a
microprocessor ? I've recently purchased a board based on the 8 MHz NEC
V25 (clone of Intel 8086 16 bit CPU) that has 11 channels of A to D, 4
channels of D to A, real time clock, digital inputs and outputs, several
16 bit timers, serial ports etc etc. This was purchased with the aim of
using it to control a 3CX5000A7 amp. AD's will be used to monitor
important voltages, currents and temperature, digital outputs will
switch the RF relays, fan, heater, HT, pre-amp relay etc etc. The DA's
will drive a SWR meter, after calculating the SWR from the forward and
reflected powers measured on the ADs'. Delays necessary while relays
switch ( to avoid hot swithching) will be done digitally. I might (at a
late date), look at possibly driving stepper motors to implement
auto-tuning.
The board purchased (V012 from Tern in the USA) is basically programmed
from a PC (in C/C++ or assembler), then the code is downloaded into
static ram (128 kb SRAM) on the board. From there the code is kept in
SRAM by a battery, which should last several years. Once the code is
working properly, an EPROM can be blown to make for permanent storage.
For those interested, the board I purchased on Friday (hence has not
arrived yet), cost about $400, including the development system to
program it. The development system (well evaluation kit to be precise)
takes about half the cost.
I would be interested in anyone who has done similar things. Any
problems ? Tips ? Can anyone see any problems ? Tthings like processor
noise are I believe controllable. I would also be interested to hear
from any owners of commercial amps that use microprocessor control. Do
you know the sort of micro used ? I did look at making a board myself,
using the Motorola HC11 microcontroller, but in the end too the easy
option.
--
Dave Kirkby G8WRB
Department of Medical Physics,
University College London,
11-20 Capper Street,
London,
WC1E 6JA.
Tel: 0171 209 6406 (International +44 171 209 6406)
Fax: 0171 209 6269 (International +44 171 209 6269)
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