Block Transfer Failure After Startup Of Transmission Across The Rio Link - Allen-Bradley 1747-SN User Manual

Block Transfer Failure After Startup of Transmission Across RIO Link
Control Flag
EN
TO
Status Flag

EW

ST
ER
DN
Block Transfer Failure after Startup of Transmission Across the RIO
Link
This example illustrates control and status changes when a BT fails
after it starts.
The SLC control program fills in the M0 BT output/control buffer
and sets the EN flag.
 The scanner detects the EN flag, validates the M0 information,
puts the BT request on the RIO link successfully, and sets the EW
and ST flags in the M1 BT input status buffer.
 The scanner receives a BT reply (with some error) from the RIO
link device, fills in the M1 BT buffer's error code field, and sets
the ER flag.
 The SLC control program detects the ER flag, examines the M1
BT buffer error code, and clears the EN flag after processing the
error.
 The scanner detects that the SLC control program has processed
the reply in the M1 BT buffer and clears the EW, ST and ER
flags.
RIO Block Transfer
M0 Control Information
M1 Status Information
5–17



 
Publication 1747 6.6 - July 1996