SBC PCD3 Series - Memory Management with Integrated μSD Card

Saia-Burgess Controls AG
Hardware manual for PCD3 series │ Document 26-789 ENG19│ 2018-06-29
Storage space on the PCD3
PCD3.Mxxx0 Classic CPU and expansion enclosure
3-51
3
 
TheμSDashcardonthesystemboardmustnotberemovedunder
anycircumstances(itincludesthermwareetc.)!
The Saia PCD3 Plus automation devices (red type plate,
PCD3.Mxx60)areequippedwithanonboardμSDashcard.
When loading a user application with Saia PG5
®
, all the
necessarylesarestoredontheμSDcard.
If the operating voltage is connected to the automation device
and there is no executable program in the user memory,
COSinusattemptstoloadavalidprogramfromtheμSDash
card into the main memory on startup.
Saia P CD3.Mxx6x
Loading of the user program from PG5® onto Saia PCD® auto-
mation devices and allocation of dierent data between the
storage media.
SRAM
Media (R, T, F)
PCD3.Mxx6x
File system

SRAM data
User program
RIO application
load as required
RAM
μSD ash card
secure on demand (backup)
User memory= RAM text/DB memory
In these systems, the RAM (Random Access Memory) includes text and DB
memoryaswellasthemedia(R,T,F).TheaddressoftherstRAMtext/DBisset
in the PG5 build options.
All texts and DBs have a maximum size of 16383 elements (DBs) respectively
65535 bytes.
ROM text/DB cannot be written to the PCD3 power CPUs, whereas it was still
possible on earlier systems. The program is always loaded on these systems on
ashinthePCDandisthereforealwaysavailableevenifthereisnobatteryThe
programisalwaysloadedonthesesystemsonashinthePCDandistherefore
always available even if there is no battery.