Rockwell Automation Publication 1756-RM003N-EN-P - October 2011 577
ASCII Serial Port Instructions (ABL, ACB, ACL, AHL, ARD, ARL, AWA, AWT) Chapter 17
ASCII Error Codes
If an ASCII serial port instruction fails to execute, the ERROR member of its
SERIAL_PORT_CONTROL structure will contain one of the following
hexadecimal error codes.
String Data Types
You store ASCII characters in tags that use a string data type.
· You can use the default STRING data type. It stores up to 82 characters.
· You can create a new string data type that stores less or more characters.
To create a new string data type, see the Logix5000 Controllers Common
Procedures Programming Manual, publication 1756-PM001
.
Each string data type contains the following members.
This hex code Indicates that the
16#2 Modem went offline.
16#3 CTS signal was lost during communication.
16#4 Serial port was in system mode.
16#A Before the instruction executed, the .UL bit was set. This prevents the execution of the instruction.
16#C The controller changed from Run mode to Program mode. This stops the execution of an ASCII serial port instruction and clears the
queue.
16#D In the Controller Properties dialog box, User Protocol tab, the buffer size or echo mode parameters were changed and applied. This
stops the execution of an ASCII serial port instruction and clears the queue.
16#E ACL instruction executed.
16#F Serial port configuration changed from User mode to System mode. This stops the execution of an ASCII serial port instruction and
clears the ASCII serial port instruction queue.
16#51 The LEN value of the string tag is either negative or greater than the DATA size of the string tag.
16#54 The Serial Port Control Length is greater than the size of the buffer.
16#55 The Serial Port Control Length is either negative or greater than the size of the Source or Destination.
Name Data Type Description Notes
LEN DINT Number of characters in
the string
The LEN automatically updates to the new count of characters whenever you:
·See the String Browser dialog box to enter characters.
·See instructions that read, convert, or manipulate a string.
The LEN shows the length of the current string. The DATA member may contain additional,
old characters, which are not included in the LEN count.
DATA SINT array ASCII characters of the
string
·To access the characters of the string, address the name of the tag.
For example, to access the characters of the string_1 tag, enter string_1.
·Each element of the DATA array contains one character.
·You can create new string data types that store less or more characters.
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