Rockwell Automation 1336T Function Block Prog. Manual, Series A/B - Manual (Page 157)

5–41 Block Transfer Services
1336 FORCE — 5.9 August 1995
The Read Node Value message reads the value of the specified
function block node.
PLC Block Transfer Instruction Data
BTW Instruction Length: 3 Words
BTR Instruction Length: 4 Words
Header
Word 1
PLC Hex Value
0F01
Message Structure
Header
Word 2
Header
Word 3
PLC Request –– Block Transfer Write
Header Word 1
Header Word 2
Header Word 3
0
Data
Word 4
0
PLC Hex Value
0F01 –– Message OK
8F01 –– Message Error
Node
Value
ID N
8NID
High Byte Low Byte
Drive Response –– Block Transfer Read
where:
N = the node number
ID = the block ID number
ID N
8NID
High Byte Low Byte
If N=16, 8NID becomes 90ID.
Message Operation
Word 3 specifies the function block node.
❒
ID indicates the block ID number is specified in the low byte.
❒
N indicates the node number is specified in the high byte (bits 8
through 14).
Example
In this example, a Read Node Value message was sent to the drive to
read the value of node 1 of the Scale function block (block ID 11
Dec
,
0B
Hex
). The drive response indicates the value of node 1 is 4.
1 0
N10:10
2 3 4 5 6 7 8 9
N10:90
BTW
Data File
BTR
Data File
Data Format
810B
810B 4
0
0
0F01
0F01
Note: The output of a Bin2Dec block is node 16
Dec
, and would be
specified as 900B if it were assigned a block ID number of 11
Dec
.
Node Adjustment:
Read Node Value
"