Rockwell Automation 1746-BAS BASIC LANGUAGE - Manual (Page 216)

Publication 1746-RM001A-US-P
13-26 Input Functions
CALL 118 – PLC/SLC
Unsolicited Writes Purpose
Use CALL 118 to allow the module to receive data packets sent by PLC-2, PLC-3,
or PLC-5 message instructions on the DF1 network. This CALL also sets up the
module to receive data packets from an SLC node on the DH485 network. Both
the DF1 port (PRT2) and the DH485 port cannot be active at the same time.
Jumper JW4 on the module is used to select your port configuration.
Any write message instruction sent to the module from these PLC/SLCs cause the
data to be placed in an internal string within the CPU M1 file, the CPU input
image file and/or the module string, starting at the designated word offset.
The low byte of the first word of the destination file contains the character count
(byte count) of the transferred data. The high byte of this word is unused. If an
internal string is chosen, the first character contains the byte count. The second
character (transaction number) of the internal string is incremented, upon
successful receipt of a packet, to inform the module that new data is in the string.
The value of this transaction number wraps around from 255 to 0.
Execute CALL 118 once. After the CALL is executed, the module checks the port
at the end of each line of BASIC code. The module gets new data from the PLC or
SLC and transfers it as described below:
1. 1. 1. 1. The module receives packets initiated from the PLC/SLC configured in the
CALL through either ports PRT2 or DH485. Both PRT2 and DH485 ports
cannot be active at the same time. Jumper JW4 is used to make this selection.
2. 2. 2. 2. The module transfers the data into the local SLC destination buffer.
SLC Processor SLC Backplane BASIC or BASIC-T Module
PORT PRT1
PORT PRT2
DF1 Network
PLC
SLC
DH485 Network
SLC Processor SLC Backplane BASIC or BASIC-T Module
DESTINATION
BUFFER