ASCII In (AIN) Instruction

Mnemonic (Keyboard Shortcut) = AIN

Icon / Button =

Purpose

Receive Raw ASCII Strings in the Serial Ports of the CPU and place the data in a String Tag.

Instruction Parameters

Parameter	Parameter Type	Requirements	Description
Enable	Ladder Input	Must Have	Level-driven. When Enable is ON, the instruction will operate every scan. When Enable is OFF, the instruction is not solved and it's outputs are not updated.
Serial Port	Drop Down Selection	Must Have	The Serial Port where ASCII data is received.
Fixed Length	Selectable Option	Must select Fixed Length or Variable Length	A specified String Length to be received. Requires a value for Number of Characters.
Number of Characters	Constant	Must Have when using Fixed Length	The Number of Characters to be received in a string when using Fixed Length.
Variable Length	Selectable Option	Must select Fixed Length or Variable Length	Specifies the Strings may have Variable Lengths. Enables Max Number of Characters, 1 Character and 2 Characters. A Termination Code MUST be specified.
Max Number of Characters	Constant	Must Have when using Variable Length	The Maximum Number of Characters allowed to be received in a string when using Variable Length.
1 Character	Selectable Option	Must select 1 Character or 2 Characters	Enables Termination Code 1 field where Termination Character must be specified.
2 Characters	Selectable Option	Must select 1 Character or 2 Characters	Enables Termination Code 1 and Termination Code 2 fields where Termination Character must be specified for both.
Termination Code 1	Selectable Option	Must have one or both when Variable Length is enabled based on 1 or 2 Characters.	Used to mark the end of a message. Must be configured using Hexadecimal format. When the Termination Code is received, the CPU moves the received ASCII characters into the specified string. Note: Termination Codes are not placed into the Destination String.
Termination Code 2	Selectable Option		Used in conjunction with Termination Code 1 to mark the end of a message. Must be configured using Hexadecimal format. When Termination Code 1 and Termination Code 2 are received (consecutively), the CPU moves the received ASCII characters into the specified string. Note: Termination Codes are not placed into the Destination String.
First Character Timeout Interval (sec)	Constant	Optional	Amount of Time (in seconds) by which a Character MUST be received after Enable is turned ON. If Time is exceeded, First Character Timeout bit will become True.
Inter Character Timeout Interval (msec)	Constant	Optional	Amount of Time (in milliseconds) that is allowed between Characters of a String. If this Time is exceeded, Inter Character Timeout bit will become True.
Do Not Clear Buffer on Input	Selectable Option	Optional	If not selected (default), any data already received will be cleared from the buffer when the instruction is started. If selected, any data already received will be used by the instruction.
Byte Swap Option	Selectable Option	Must Have No Byte Swap, All Characters, or All But NULL Characters selected.	No Byte Swap: No Bytes will be Swapped. All Characters: Every 2 Characters will be Swapped when placing the data into the Destination Tag Name. All But Null Characters: Every 2 Characters will be Swapped except Null Characters when placing the data into the Destination Tag Name.
Convert NULL to 0x	Selectable Option	Optional	Convert NULL Character to the Character specified to avoid early termination of a string.
Destination	String Tag	Must Have	The Tag to place the String data.
Use Structure	Selectable Option	Optional	If selected (not default), the selected Structure data type from the drop menu will be used for the instruction.
Number of Characters Received	Numerical Tag	Optional	Value of Total Characters received.
In Progress	Boolean Tag	Optional	If "Do Not Clear Buffer" is NOT selected, this bit is ON until the Enable is removed. If "Do Not Clear Buffer" is selected, then this bit will go low in certain conditions (see timing charts below).
Complete	Boolean Tag	Optional	Enabled when CPU has received data into the specified serial port that meets the criteria (size or termination received) of the Enabled instruction. Turns OFF when instruction is Re-enabled or if the user manually clears the tag while the instruction is still Enabled.
Success	Boolean Tag	Optional	Enabled when Complete has occurred with no Error bits. Turns OFF when instruction is Re-enabled or if the user manually clears the tag while the instruction is still Enabled.
First Character Timeout	Boolean Tag	Optional	A Character MUST be received within the specified Time period after instruction Enable is turned ON or 1st Character Timeout bit will turn ON.
Inter Character Timeout	Boolean Tag	Optional	Each Character MUST be received within the specified Time period up until the Complete bit is turned ON or the InterCharacter Timeout bit will turn ON.
Overflow	Boolean Tag	Optional	Turns ON if the CPU receives more Characters than specified in the Max Number of Characters before seeing the Termination Character(s) specified. The Overflow Error bit will turn OFF again when new data is received.

Note: When Enable turns ON, the buffer of the specified Serial Port is Cleared.

Note: If any incoming string contains Extended ASCII characters, the Extended ASCII characters will be discarded.

Instruction Configuration

When ASCII In Instruction is selected the window shown below opens.

Parameter Configuration Table

ASCII In

Instruction

(AIN)

Notes

Serial Port

Select a Serial Port

Fixed Length

Select for Fixed Length.

Number of Characters

Enter a value for Number of Characters for Fixed Length.

Variable Length

Select for Variable Length.

Max Number of Characters

Enter a value for the Maximum Number of Characters for Variable Length.

1 Character

Select for Variable Length 1 Character.

2 Characters

Select for Variable Length 2 Characters.

Termination Code 1

Enter a Hexadecimal value.

Termination Code 2

Enter a Hexadecimal value.

First Character Timeout Interval

Enter Time (in seconds) for setting First Character alarm.

Inter Character Timeout Interval

Enter Time (in milliseconds) for setting Inter Character alarm.

Do not Clear Buffer on Input

Select to use the data already received.

Byte Swap Option

Select a Byte Swap option.

Convert NULL to 0x

Select the checkbox and enter a Character to store if NULL is received.

Use Structure

Select to select a Structure Data Type to use with instruction.

Destination

Select String Destination.

Number of Characters Received

Select a Tag for Number of Characters of Current Count.

In Progress

Select a Boolean Tag for the In Progress bit status.

Complete

Select a Boolean Tag for the Complete bit status.

Success

Select a Boolean Tag for the Success bit status.

First Character Timeout

Select a Boolean Tag for the First Character Timeout alarm bit status.

Inter Character Timeout

Select a Boolean Tag for the Inter Character Timeout alarm bit status.

Overflow

Select a Boolean Tag for the Overflow alarm bit status.

Application Example

In this example, a Barcode String is transferred into the Communications Port of the CPU. The String is terminated with a carriage return (0x0D).