6: D
EVICE
A
DDRESSES
FC5A M
ICRO
S
MART
U
SER
’
S
M
ANUAL
FC9Y-B1268
6-31
Data Movement of Preset Data Registers
Like preset values for timers and counters (page 7-18), the preset data of expansion data registers can be changed in the
RAM, the changed data can be cleared, and also stored to the ROM. The data movement is described below.
At Power-up and User Program Download
WindLDR
MicroSmart CPU Module
Download
User Program
ROM
RAM
User Program
Preset
Values
When the user program is downloaded to the CPU
module, the data of preset data registers are also
downloaded to the ROM. Each time the CPU is pow-
ered up, the data of preset data registers are loaded
to the RAM. If the data of the expansion data regis-
ters have been changed as a result of advanced
instructions or through communication, the changed
data is cleared and initialized with the data of the
preset data registers when the CPU is powered up
again.
Since expansion data registers D2000 through D7999 are all “keep” types, the data in ordinary data registers are retained
when the CPU is powered down.
Initializing Relay
MicroSmart CPU Module
Initialize
User Program
ROM
RAM
Preset
Values
When the internal relay designated as an initializing relay is turned on,
the data of preset data registers are loaded to the RAM as is the case
when the CPU is powered up.
When the initialization is complete, the initializing relay is turned off
automatically. When a user program is used to turn on the initializing
relay, use a SOTU or SOTD to make sure that the initializing relay turns on
for one scan only. When an initializing relay is not designated, the initial-
ization cannot be performed.
Backup Relay
MicroSmart CPU Module
Backup
User Program
ROM
RAM
Changed
Values
When the internal relay designated as a backup relay is turned on, the
data of preset data registers are written from the RAM to the ROM as is
the case with confirming changed timer/counter preset values. When the
CPU is powered up again, the new data is loaded from the ROM to the
RAM. When the user program is uploaded to WindLDR, the new data is
also uploaded to the expansion data registers.
When the backup is complete, the backup relay is turned off automati-
cally. When a user program is used to turn on the backup relay, use a SOTU or SOTD to make sure that the backup relay
turns on for one scan only. When a backup relay is not designated, the backup cannot be performed.
Special Internal Relays for Expansion Data Registers
While data write from the RAM to expansion data register preset range 1 or 2 in the ROM is in progress, special internal
relay M8026 or M8027 turns on, respectively. When data write is complete, the special internal relay turns off.
Notes for Using Expansion Data Registers:
All expansion data registers are “keep” types and cannot be designated as “clear” types using the Function Area Settings.
When expansion data registers are designated as source or destination devices of advanced instructions, the execution time takes
slightly longer compared with ordinary data registers D0 through D1999.
When a user program RAM sum check error has occurred, the data of preset expansion data registers are loaded to the RAM as is the
case when the CPU is powered up.
When the initializing relay is turned on, the scan time is extended until the data load from the ROM is completed by approximately 7
ms for every 1000 words of data read from the ROM. The data size can be calculated from the following formula:
Data size (words) = 8.5 + Quantity of preset data registers
When the backup relay is turned on, the scan time is extended until the data write to the ROM is completed for several scans by
approximately 200 ms in every scan.
Writing to the ROM can be repeated a maximum of 100,000 times. Keep writing to the ROM to a minimum.
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