User manual

Chapter 4
Ladder-Program Interfaces
4-6
The PLC-5/VME processor manipulates only two of the status bits in the
control word of the internal message control block:
DN (done)
ER (error)
For the copy operations, DN is not set until and unless the data are
successfully transferred. If an error occurs, ER is set and an error code is
placed in the message control block.
For the SVI operation, DN is set if and when the interrupt-acknowledge
cycle is successfully performed by the interrupt handler. If the message
syntax is incorrect (interrupt is not 1-7 or status/ID is not two hexadecimal
digits), ER is set along with an error code. For the CSF operation, DN is
set immediately.
For unrecognizable messages, ER is set along with an error code. The
error codes are:
Code Explanation
0000H Success
0001H Invalid ASCII message format
0002H Invalid file type
0003H invalid file number
0004H Invalid file element
0005H Invalid VME address
0006H Invalid VME transfer width
0007H Invalid number of elements requested for transfer
0008H Invalid VME interrupt level
0009H Invalid VME interrupt status-id value
000AH VMEbus transfer error (bus error)
000BH Unable to assert requested interrupt (already pending)
000CH Raw data transfer setup error
000DH Raw data transfer crash (PLC switched out of run mode)
000EH Unknown message type (message type not ASCII)
If the PLC-5/VME processor receives the same message control block with
the same msg_address field from the processor core with the .TO (timeout)
bit set, the current operation is terminated.
Message Completion and
Status Bits