The data storage is used for READ_U_PCMCIA and WRITE_U_PCMCIA function blocks.
Lets say for e.g.. you configure the Data storage size as 2000 kB then the 2000 kB of data storage represents:
2000 kiloBytes * 1024 = 2048000 Bytes
Since The READ_U_PCMCIA and WRITE_U_PCMCIA functions are working with word addresses:
So 2048000 Bytes / 2 = 1024000 Words
Hence Addresses from 0 to 1024000 for the memory card can be used for data storage.
In the MAST section of the program, program as follows:
The memory card is connected into slot 0.
The WRITE_U_PCMCIA function writes 10 words to address 10000 on the memory card from %MW100.
The READ_U_PCMCIA reads 10 words from address 10000 on the memory card to %MW110.
Representation of WRITE_U_PCMCIA and READ_U_PCMCIA in ST language:
WRITE_U_PCMCIA (0,10000,10,100,Status_write);
READ_U_PCMCIA (0,10000,10,110,Status_read);
Basically The WRITE_U_PCMCIA function transfers data from the PLC RAM memory to the user memory card archiving zone and The READ_U_PCMCIA function transfers data from the user memory card archiving zone to the PLC RAM memory. The function READ_U_PCMCIA allows addressing the PLC zone's beginning to be copied to the PCMCIA card up to 65 535.
Lets say for e.g.. you configure the Data storage size as 2000 kB then the 2000 kB of data storage represents:
2000 kiloBytes * 1024 = 2048000 Bytes
Since The READ_U_PCMCIA and WRITE_U_PCMCIA functions are working with word addresses:
So 2048000 Bytes / 2 = 1024000 Words
Hence Addresses from 0 to 1024000 for the memory card can be used for data storage.
In the MAST section of the program, program as follows:
The memory card is connected into slot 0.
The WRITE_U_PCMCIA function writes 10 words to address 10000 on the memory card from %MW100.
The READ_U_PCMCIA reads 10 words from address 10000 on the memory card to %MW110.
Representation of WRITE_U_PCMCIA and READ_U_PCMCIA in ST language:
WRITE_U_PCMCIA (0,10000,10,100,Status_write);
READ_U_PCMCIA (0,10000,10,110,Status_read);
Basically The WRITE_U_PCMCIA function transfers data from the PLC RAM memory to the user memory card archiving zone and The READ_U_PCMCIA function transfers data from the user memory card archiving zone to the PLC RAM memory. The function READ_U_PCMCIA allows addressing the PLC zone's beginning to be copied to the PCMCIA card up to 65 535.
Released for:Schneider Electric India

