Example Slc Block Transfers - Allen-Bradley 1203 Series User Manual

Example SLC Block Transfers

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Figure 5.5 and the following data file illustrate an example block
transfer program from an SLC controller to a Remote I/O
communications module. This program uses the first block transfer
area in the scanner located in the first slot. It also uses data files N10
and B3.
The example data file contains the data needed to request a read full
of parameter 78. The length of the block transfer data file is loaded
into N10:1. The value 0 is loaded into N10:2 for the rack, group, slot
address for the block transfer because this address is 0, 0, 0 (refer to
page 5–7). Data for the BTW is loaded into N10:10. Once the data
has been loaded, the user enabled bit B3:0/0 is set. When the block
transfers have completed, the BTR data is copied into N10 starting at
N10:100 and B3:0/0 is cleared by the program.
Figure 5.5.
This rung clears the Virtual BT Command word on the first scan.
This ensures that the Block Transfer logic starts up reliably.
First Pass
S:1
15
This rung copies the BT Status buffer from the 1747-SN into the SLC into a
file that we will refer to as the Virtual BT Status Buffer.
If the user logic is calling for a Block Transfer message to occur and the Gx1 is ready to receive a BTW,
this rung sets up the BT buffer for a BTW and then enables it.
User BTR BTW
Logic Available Available
B3:0 I:1.0 I:1.0
0 10 13
1747-SN 1747-SN
This rung turns off the Virtual BT_Enable bit when the BTW has completed.
Virtual
BT.Type
Bit Virtual
0 = BTW BT.DN
1 = BTR Bit
N10:0 N10:100
7 13
Using Block Transfer Messages
Example for an SLC-500
Virtual
BT.EN
Bit
N10:0
15
5–5
MOV MOV
Move
Source 0
0<
Dest N10:0
-32640<
COP COP
Copy File
Source #M1:1.100
Dest #N10:100
Length 74
Virtual
BT.Type
Bit
0 = BTW
1 = BTR
N10:0
U
7
Virtual
BT.EN
Bit
N10:0
L
15
Virtual
BT.DN
Bit
N10:100
U
13
Virtual
BT.EN
Bit
N10:0
U
15