Rockwell Automation 6008-SI IBM PC I/O SCNNR 6008-SI - Manual (Page 79)

Chapter 7
Scanner Management
7-12
The scan list request is the only MR that requires both data and length of
data to be in the packet before you call mr_wait. The first argument to
mr_wait is C_SCANLIST. The scanner must be in program mode to
execute a scan list request; otherwise the scanner just returns an error code.
Calling sequence:
packet.qmr_len = . . . /* length of scan list, 0-64 */
packet.qmr_data[0] = . . . /* first adapter address */
packet.qmr_data[1] = . . . /* second adapter address */
. . .
packet.qmr_data[length-1] = . . . /* last adapter address */
status = mr_wait(C_SCANLIST,
&packet
);
where
packet is a QMR type packet. Note that the argument to mr_wait is a
pointer to the packet.
packet.qmr_len, the length of the scan list, may be anything from 0 to
64 inclusive.
packet.qmr_data contains the adapter addresses for the scan list, in the
form 4 x rack + starting group / 2. A given adapter can occur more than
once in the list, or an existing adapter may be omitted from the scan list.
Returned values:
status and packet.qmr_stat as explained under General Form, above.
The time required to complete a scan list command is essentially the
time to scan every adapter once: 11 milliseconds per scan list entry (7
ms/entry at 115.2 Kbaud). Since the scan list can be as long as 64
entries, the worst case time is 704 ms at 57.6 Kbaud, 448 ms at 115.2
Kbaud.