User's Manual

545C Operations Manual

02/10/2012 Prerelease DCN 00001789-A

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 design, the MCC-545C has three types of memory:

1. Program Memory (PM)

2. Random Access Memory (RAM)

3. Configuration Parameter (CPM)

The PM is non-volatile flash 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 into the MCC-545C operating

system software at the factory. The PM can only be modified by replacing

the operating system using the flash download. (Consult XTermW manual to

learn how to download a new flash into the PM.)

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 or Ni Metal Hydride battery (internal to

the unit) 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.

The third type of memory, CPM, is also nonvolatile flash memory and

retains data even when power is removed. The MCC-545C retains a copy of

all the programmed configuration parameters in CPM. The MCC-545C will

write configuration parameters, that have been entered from the operator

port, into CPM when the SAVE command is entered. Only values that have

changed are written into CPM. Whenever the unit radio ID is changed the

MCC-545C will automatically SAVE the configuration. A validation checksum