ACB (ASCII characters in buffer)

The ACB instruction counts the total number of ASCII characters in the buffer, including end of line.
Languages supported: Function block diagram, ladder diagram, structured text.
This instruction applies to the L20E, L50E, and L70E controllers.
ACB
ACB
ACD parameters
Parameter
Parameter Type
Data Type
Description
IN
Input
BOOL
Rung input state.
  • TRUE: When Rising Edge is detected, start the instruction block with the precondition that the last operation is complete.
  • FALSE: The instruction block is idle.
ACBInput
Input
ABLACB
The channel to be operated.
Use the ABLACB data type to define the Channel, TriggerType, and Cancel parameters for ACBInput.
Q
Output
BOOL
Indicates whether the character count is ongoing or complete.
Outputs of this function block are updated asynchronously from the program scan. Output Q cannot be used to re-trigger the instruction because IN is edge triggered.
  • TRUE: The counting is complete.
  • FALSE: The counting is ongoing.
Characters
Output
UINT
The number of characters in the buffer.
Error
Output
BOOL
Indicates the existence of an error condition.
  • TRUE : An error is detected.
  • FALSE: No error.
ErrorID
Output
UINT
A unique numeric that identifies the error. The errors for this instruction are defined in ABL error codes.
ACB error codes
Error Code
Error Description
03
Transmission cannot be completed because the Clear-to-Send signal was lost.
06
Illegal parameter was detected.
07
Cannot complete ASCII send or receive because channel configuration has been shut down using the channel configuration dialog.
08
Cannot complete ASCII Write due to an ASCII transmission already in progress.
09
ASCII communication requested is not supported by current channel configuration.
10
The Cancel was set, stopping instruction execution. No action required.
11
The requested length for the string is either invalid, a negative number, greater than 82, or 0. Applies to ARD and ARL function blocks.
13
The requested (.LEN) in the control block is a negative number or a value greater than the string size stored with the source string. Applies to AWA and AWT function blocks.
14
The ACL function block was canceled.
16
Serial port is not supporting RTS or CTS control lines.

ACB examples

ACB function block diagram example
ACB function block diagram example
ACB ladder diagram example
ACB ladder diagram example
ACB structured text example
ACB structured text example
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