Rockwell Automation 1771-IR , D17716.5.76 RTD INPUT MODULE - Manual (Page 55)

Appendix
D
DĆ1
Block Transfer (Mini-PLC-2 and PLC-2/20
Processors)
Programming multiple GET instructions is similar to block format instructions
programmed for other PLC–2 family processors. The data table maps are
identical, and the way information is addressed and stored in processor memory
is the same. The only difference is in how you set up block transfer read
instructions in your program.
For multiple GET instructions, individual rungs of ladder logic are used instead
of a single rung with a block transfer instruction. A sample rung using multiple
GET instructions is shown in Figure D.1 and described in the following
paragraphs.
Rung 1: This rung is used to set four conditions.
Examine On Instruction (113/02) – This is an optional instruction. When
used, block transfers will only be initiated when a certain action takes place.
If you do not use this instruction, block transfers will be initiated every I/O
scan.
First GET Instruction (030/120) – identifies the module’s physical address
(120) by rack, group and slot; and where in the accumulated area of the data
table this data is to be stored (030).
Second GET Instruction (130/060) – indicates the address of the first word
of the file (060) that designates where the data will be transferred. The file
address is stored in word 130, 100
8
above the data address.
Output Energize Instruction (012/07) – enables the block transfer read
operation. If all conditions of the rung are true, the block transfer read enable
bit (07) is set in the output image data table control byte. The output image
table control byte contains the read enable bit and the number of words to be
transferred. The output energize instruction is defined as follows:
- ”0” indicates that it is an output instruction
- ”1” indicates the I/O rack address
- ”2” indicates the module group location within the rack
- ”07” indicates this is a block transfer read operation (if this were a block
transfer write operation, ”07” would be replaced by ”06”.)
Multiple GET Instructions -
Mini-PLC-2 and PLC-2/20
Processors