Meteor Communications Corporation MCC-545C, Эксплуатация и обслуживание, Страница: 39 / 88

OPERATIONS 4-3
MCC-545C PACKET DATA RADIO
12/2000
Finally, enter the SAVE command to write the configuration into the EEPROM for non-volatile
storage.
4.2.1 Configuring the MCC-545C
Configuration parameters include the unit ID, the Master Station assignment, I/O port functions
and baud rates, transmit and receive parameters and network parameters. Commands which
allow you to display/modify the configuration are marked with an * in the command table.
Parameters or operational states set by these commands are retained and will determine the way
in which the MCC-545C will interact with other equipment at the site and with the
communications network.
Most configuration parameters can be viewed with the "CONFIG" and the "ASSIGN"
commands. You should use these commands to verify that the configuration is correct. If it is not
correct, use the appropriate command(s) to correct the configuration, then enter the "save"
command to write the configuration parameters into the EEPROM.
Saving and Restoring the Configuration - The Theory
To aid your understanding how the MCC-545C operational configuration is saved and restored it
is helpful to understand the hardware and design philosophy of the MCC-545C.
The MCC-545C is designed to operate unattended in a variety of environments where power
may be applied continuously or intermittently. The goal is for the unit to continue to operate
without loss of messages, data or configuration even if power is randomly turned on and off.
Therefore the software is designed to operate continuously, to save all operational information
when power is off and to resume operation from that point when power is restored.
To support this philosophy, the MCC-545C has three types of memory: PROM, RAM and
EEPROM. The PROM is non-volatile memory that has been programmed with the MCC-545C's
operational software. This software contains the initial values of all operational parameters. The
values are referred to as the "factory defaults" because they are programmed in the factory when
the unit is first manufactured. The PROM can only be modified by replacing this chip with one
programmed with the new data.
The RAM contains all the dynamic data for the MCC-545C. All data logger data, positional data,
and messages entered into the MCC-545C are stored in RAM. Also, all command parameters are
stored in RAM. But RAM is volatile and can only retain information while power is applied.
Turning off or disconnecting power will cause all RAM information to be lost. To prevent this, a
small internal NiCad battery is used to maintain power to the RAM when external power is off.
During normal operation, the MCC-545C software operates from the data and the parameters
that are stored in RAM. Unfortunately, there are always situations when the RAM data may be
lost or corrupted due to total discharge of the battery, software crash or operator error. Since we
do not want to lose our configuration data during these situations, we have a third type of
memory.