M0 File Bt Control Buffer Layout; Bt Control Flag Definitions - Allen-Bradley 1747-SN User Manual

M0:e.103 through M0:e.109 – These words are reserved.
M0:e.110 through M0:e.173 – BTW data Words 0 through 63.

M0 File BT Control Buffer Layout

Important:
The buffer layout below is the same for all 32 BT
buffers. Buffer 1 = M0:e.100... buffer 32 = M0:e.3200.
BT Control Buffer Function
Control Flags - See Control Flag
Definitions table below.
BT Length - 0 through 64
BT Address (logical rack, group, and
slot)
Reserved
BTW Data Locations 0 through 63

BT Control Flag Definitions

Definition
These bits are reserved.
Type of BT operation (1 = BTR and
0 = BTW)
Block Transfer Timeout (TO) = 1 =
Cancel the BT operation.
These bits are reserved.
Block Transfer Enable (EN) = 1 =
Enable the BT operation.
Bit 7 indicates whether the SLC control program is initiating a BTR or a BTW.
You set bit 8 (timeout bit - TO) = 1 to cancel a BT. You can cancel a BT operation (by timing out)
once the Enabled Waiting (EW) bit sets and before the RIO scanner's internal four second BT
timer times out or the BT completes. Cancelling a BT causes an error (ER) bit to set and an error
code to display in the M1 BT buffer. Note that the Timeout (TO) flag must be cleared before
initiating a new BT. (You can initiate a new BT by clearing the EN flag, waiting for the ER flag to
clear, and then setting the EN bit.) The RIO scanner will ignore a BT request if both TO and EN
flags are set at the same time.
You set bit 15 = 1 to Enable (EN) a BT operation. You set this bit after you have entered all other
control information i.e., bits 7 and 8 in the M0 BT buffer. You clear this bit after either the Done
(DN) or Error (ER) bits are set in the M1 Status file. See the M1 file BT Buffer Layout section for
more details on the DN and ER bits.
RIO Block Transfer
M0 Address where x = buffer # from 1 to 32
M0:e.x00
M0:e.x01
M0:e.x02
M0:e.x03 through M0:e. x09
M0:e.x10 through M0:e.x73
Control flags where x = buffer # from 1 to 32
M0:e.x00/0 through M0:e.x00/6
M0:e.x00/7
M0:e.x00/8
M0:e.x00/9 through M0:e.x00/14
M0:e.x00/15
Publication 1747 6.6 - July 1996
5–9