Publication 1762-RM001C-EN-P
ASCII Instructions 20-23
Instruction Operation
When the rung goes from false-to-true, the Enable bit (EN) is set. When
the instruction is placed in the ASCII queue, the Queue bit (EU) is set. The
Running bit (RN) is set when the instruction is executing. The DN bit is set
on completion of the instruction.
Once the requested number of characters are in the buffer, the characters
are moved to the destination string. The number of characters moved is
put in the POS field of the control data file. The number in the POS field
is continuously updated and the Done bit (DN) is not set until all of the
characters are read.
ARL - ASCII Read Line
Instruction Type: output
Use the ARL instruction to read characters from the buffer, up to and
including the Termination characters, and store them in a string. The
Termination characters are specified via the Channel Configuration screen.
Entering Parameters
Enter the following parameters when programming this instruction:
•
Channel is the number of the RS-232 port, Channel 0. (For the
1764-LRP only, you can select either Channel 0 or Channel 1).
•
Destination is the string element where you want the string stored.
•
Control is the control data file. See page 20-6.
•
String Length (LEN) is the number of characters you want to read
from the buffer. The maximum is 82 characters. If you specify a length
larger than 82, only the first 82 characters are read and moved to the
destination. (A length of “0” defaults to 82.) This is word 1 in the
control data file.
NOTE
For information on the timing of this instruction, see the
timing diagram on page 20-28.
EN
DN
ER
ARL
ASCII Read Line
Channel 0
Dest ST10:5
Control R6:4
String Length 15<
Characters Read 0<
Error 0<
ARL
Table 20.25 Execution Time for the ARL Instruction
Controller When Instruction Is:
True False
MicroLogix 1200 Series B, FRN 3 or later 139.7
µ
s + 50.1
µ
s/character 11.7
µ
s
MicroLogix 1500 Series B, FRN 4 or later 114
µ
s + 44.3
µ
s/character 10.6
µ
s
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