Block Transfer Failure At Startup - Allen-Bradley 1747-SN User Manual

5–16 RIO Block Transfer
Publication 1747 6.6 - July 1996
Control Flag
EN
TO
Status Flag
EW
ST

ER
DN

Block Transfer Failure at Startup

In the above example, the scanner found invalid control information
(e.g., an improper logical address) in the M0 block transfer control
buffer.
The SLC control program fills in the M0 BT buffer and sets the
EN flag.
 The scanner detects that the EN flag is set, determines that there
is some invalid information in the M0 control buffer, fills in the
M1 BT buffer status error code field, and sets the ER flag.
 The SLC control program detects the ER flag, examines the M1
BT status buffer error code, and clears the EN flag after
processing the error.
 The scanner detects that the SLC control program has processed
the error and clears the ER flag.
Note that in this example the EW and ST flags never set. Also, the
SLC control program must clear the EN flag in order to start a new
BT after the error has been corrected.
Block Transfer Failure at Startup
M0 Control Information

M1 Status Information