MAGNET POWER SUPPLY SYSTEM 9100
52
DANFYSIK A/S - DENMARK.
4.2
M-Panel
The M-panel is the user interface for reading current, voltage, status and making settings to the
MPS. The display has a resolution of 240*64.
The display board is built upon a micro-processor IC2, which communicate to the control
module via RS422 interface.
4.3
I-Loop, Control, Interlock PCB
The control board contains DAC for the set value, ADC for the read back, Peltier control,
DC/DC converter, serial interface, loop control, interlock and the controlling micro-processor
with external memory.
4.3.1
Micro-processor
The micro-processor is the intelligent part of the system. It consists of the micro-processor
U212, a CPLD U213, external static memory (SRAM) U214
and 3-8 decoder U211.
The micro-processor is of the type ATMEGA128 from Atmel and the CPLD is an AFT1502
from Atmel.
The CPU runs at 14.7456 MHz, controlled from the crystal Y202.
The micro-processor has built-in "Watchdog" circuit and will reset the CPU, if it for some
reason stops refreshing the watchdog.
As memory it uses its internal FLASH EEPROM for bootstrap loader and U214 with 1Mbit
capacity for the PGM storage. The PLD chip U213 generates the lower address lines as well as
the chip select signal for the SRAM. U211 74HCT138 3-8 decoder provides chip select signal
for DAC, ADC, interlocks, external status and display board.
4.3.2
DAC Circuit
The DAC circuit converts the serial digital set value to a voltage reference.
The circuit is built around U701, U702 and U705. U701 and U702 is connected to perform a
20 bit DAC used for setting the current, 19 bit plus sign while U705 is used for setting the
output voltage in the voltage mode.
The DAC circuit delivers an output voltage proportional to the digital input value.
The Digital to Analogue Converter sets the output current level in local/remote mode.
