1747-6.22, Backup Scanner User Manual

Directional Repeating Block Transfer Example
RIO Block Transfer 7-133
The following example shows a directional repeating block transfer.
This means that block transfer reads are sent repeatedly, as fast as
possible. Use the same method for a BTW.
Rung 2:0
Configure the BTR operation type, length and RIO address at power-up. Bit B3:100/7 must be set prior
| to going to run to indicate a BTR operation.
|
| |
| |
| POWER±UP BTR |
| BIT CONTROL |
| S:1 +COP---------------+ |
|----] [--------------------------------------------------+COPY FILE +-
| 15 |Source #B3:100| |
| |Dest #M0:1.100| |
| |Length 3| |
| +------------------+ |
Rung 2:1
Copy the BTR status area to a binary file, which is used throughout the program. This avoids addressing the M1 file
multiple times during each program scan. Each time an instruction containing an M-file bit, word or file is scanned by the
| processor, an immediate data transfer to the module occurs and therefore will impact the overall processor scan time. |
| |
| |
| BTR |
| PENDING BTR STATUS |
| B3 +COP---------------+ |
|-+----] [-----+------------------------------------------+COPY FILE +-
| | 80 | |Source #M1:1.100| |
| | | |Dest #B3:0| |
| | | |Length 4| |
| | | +------------------+ |
| | | |
| | | |
| | | |
| | CHECK BTR | |
| | STATUS | |
| | B3 | |
| +----] [-----+ |
| 81 |
Rung 2:2
Unlatch the bit that continues to check the BTR status. When a BTR is complete, the done or error bit is set. The
ladder program must then unlatch the enable bit, then wait for the SN module to turn off the done/error bit before
| another BTR to the same M-file location can be initiated. this is one complete BTR cycle.
|
| |
| VIRTUAL |
| BTR DONE CHECK BTR |
| BIT STATUS |
| B3 B3 |
|-+====]/[-----+-------------------------------------------------------(U)-----
| | 13 | 81
| | |
| | |
| | |
| | |
| | VIRTUAL |
| | BT ERROR |
| | BIT |
| | B3 |
| +----]/[-----+
| 12
Publication 1747-6.22