1747-6.22, Backup Scanner User Manual

7-136 RIO Block Transfer
Publication 1747-6.22
Directional Non-Continuous Block Transfer Example
The following rungs demonstrate a directional non-continuous block
transfer. The block transfer executes once for every false-to-true
transition of the input. Please note that the input bit I:2.0/0 was
chosen randomly for this example and can be any address in your
program used to initiate a BTR. Also note that this same method may
be used 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 M1 file bit, word or file is scanned b
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 | |
| | BTR ERROR | |
| | BIT | |
| | B3 | |
| +----]/[-----+ |
| 12 |