Rockwell Automation 1746-BAS BASIC LANGUAGE - Manual (Page 198)

Publication 1746-RM001A-US-P
13-8 Input Functions
CALL 27 – Read Remote
DH485 SLC Data File Purpose
Use CALL 27 to read up to 64 words of data from a remote DH485 node data file
to the local CPU input image file, the CPU M1 file, and/or a string within the
module.
If an internal string is chosen, the first character is incremented to inform the
module that new data is in the string. The value of this character wraps around
from 255 to 0.
Execute CALL 27 once to set up the data transfer parameters. Input and output
image bits (word 0, bit 10) for the slot containing the module, are used to initiate
and notify completion of the transfer. The module sends the READ command
configured in CALL 27 to the designated remote DH485 device on the network.
The operation is described below:
1. 1. 1. 1. The local SLC processor sets the output file word 0, bit 10 to inform the
module that the READ command configured in CALL 27 should be executed.
2. 2. 2. 2. The module automatically issues the appropriate READ command to the
remote device on the DH485 network. The data and status are sent back to the
local SLC processor.
3. 3. 3. 3. When data is available, the module transfers the data into the local SLC
destination buffer.
SLC Processor SLC Backplane BASIC or BASIC-T Module
Output File
Word 0, Bit 10
SLC Processor SLC Backplane BASIC or BASIC-T Module DH485 Network Remote Device
READ Command
Data and Status
PORT DH485
SLC Processor SLC Backplane BASIC or BASIC-T Module
DESTINATION
BUFFER