4-4
888-2523-001
7/26/05
WARNING: Disconnect primary power prior to servicing.
Section 4 Theory of Operation
ATLAS Analogue
Features of the 376 module include:
a.
Built-in CAN (Controller Area Network) bus controller
b.
16 A/D inputs for analog metering
c.
A serial EEPROM for non-volatile memory storage
d.
A built in clock running at 4.194MHz which will let the micro run at 16-25MHz
e.
Power failure detection
f.
A watchdog which will reset the micro if it is not triggered at least every 1.6
seconds (this time interval will change depending on the application). A discrete
logic device or CPLD is almost always provided on the motherboard to act as an
I/O expansion device and in some cases as life support if the micro module fails.
g.
Multiple I/O lines whose direction of signal flow is based on the flash memory
programming. These could be control or status, inputs or outputs, depending on
the particular use.
The main responsibility of the micro module is control of the CPLD and the reporting
and receiving of information over the CAN bus. This means that the CPLD will
continue to monitor and protect the systems to which it is connected even if the micro
module fails. However, there will be no reporting of information to the rest of the
transmitter system since access to the CAN bus is gone without the micro module.
4.3.2
CPLD, Complex Programmable Logic Device
The transmitter control boards with the micro module also incorporate a CPLD
(Complex Programmable Logic Device) with the exception of the module controllers.
The CPLD is not a microprocessor but is actually just programmed discrete logic and is
therefore very stable and reliable. The CPLDs in the transmitter perform two vital
functions in terms of control and transmitter monitoring:
a.
I/O Expansion
b.
Life Support Backup
4.3.2.1
I/O Expansion
Each Micro Module only has a limited number of Input/Output or I/O lines available.
The CPLDs provide a way to easily expand the available I/O ports on each control
board. Basically, the CPLDs are actually controlling and monitoring the I/O for each
control board. The micro module is taking that information and relaying it, via the CAN
bus, to the Main Controller for display on the front panel control screen or a remote
Summary of Contents for ATLAS ANALOGUE
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