Custom Protocol In (CPI) Instruction

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.

Drop Down Selection

Must Have

The Serial Port where ASCII data is received.

Constant

Must Have

The number of Bytes (1-4) to be copied into the Data Tag.

Numerical Tag

Must Have

Data Tag to place the Data extracted from the specified Offset and Length.  The Data will be formatted to the specified Data Type of the Data Tag.

Checkbox Option

Optional

Every Two Characters will be Swapped when Data is received.

Checkbox Option

Optional

Select if Checksum calculation is to be performed on Data Received.

Drop-Down Selection

Must Have if Checksum is selected

Type of CRC (Cyclic Redundancy Check) or XOR calculation to perform on the Received Data.  This needs to match the calculation method of the Sending device.  Enabled when Checksum option is selected.

Constant

Determines where instruction should obtain embedded Checksum value from the data received in order to Compare to the value calculated from the Checksum Range selection.  Enabled when Checksum option is selected.

Selectable Option

Determines whether the sending device sets the CRC or XOR value as High Byte first or Low Byte first.  Enabled when Checksum option is selected.

Selectable Option

Determines which Bytes of the received data should be used in the Checksum Calculation.  Enabled when Checksum option is selected.

Checkbox Option

Optional when Checksum is selected

Different Checksum calculations use different preloads for the calculation.  Check the sending device technical documentation to determine this value.  Enabled when Checksum option is selected.

Selectable Option

Must Have Fixed or Variable Length Selected

Sending device will be sending a Fixed number of characters.  This requires no check for a termination character.

Constant

Must Have when using Fixed Length

Specifies the Number of Characters that will be received from the sending device.  Enabled when Fixed Length option is selected.

Selectable Option

Must Have Fixed or Variable Length Selected

Sending device will be sending Variable Length packets and a termination character check is necessary in order to determine  which data should be received from the port.

Constant

Must Have when using Variable Length

Specifies the Maximum Number of Characters that will be received from the sending device.  Enabled when Variable  Length option is selected.

Selectable Option

Must have 1 Character or 2 Characters selected when using Variable Length.

First Termination Character in Hex format.  Consult an ASCII table for this value.  Enabled when Variable Length option is selected.  Enables Termination Code 1 field where Termination Character must be specified.

Selectable Option

Second Termination Character in Hex format.  Consult an ASCII table for this value.  Enabled when Variable Length option is selected.  Enables Termination Code 1 and Termination Code 2 fields where Termination Character must be specified for both.

Constant

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 sent, the CPU moves the received ASCII Charactersinto the specifiedTags.  Note: Termination Codes are not placed into the ASCII String.

Constant

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 sent (consecutively), the CPU moves the received ASCII Characters into the specified Tags.  Note: Termination Codes are not placed into the ASCII String.

Constant

Must Have

Amount of Time (in seconds) by which a Character MUST be received after Enable is turned ON to the instruction.  If Time is exceeded, First Character Timeout bit will become True.

Constant

Must Have

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.

Boolean Tag

Optional

Enabled when the instruction has been Enabled.  It will go OFF once the Complete Bit is turned ON or Enabled  is removed from instruction.

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.

Boolean Tag

Optional

Enabled when Complete has occurred with no Error bits.  Turns OFF when instruction is Re-enabled.

Boolean Tag

Optional

Bit Tag is ON when Checksum has detected an Error.

Boolean tag

Optional

A Character must be received within the specified Time period after instruction Enable turns ON or the First Character Timeout Bit will turn ON.

Boolean tag

Optional

Each Character must be received within the specified Time period until the Complete Bit is turned ON or the Inter Character Timeout Bit will turn ON.

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.

Checkbox

Optional

Enables the use of Structures.

Select a Serial Port

Enter a Value Tag for Data Length.  1 to 4 Bytes.

Select a Tag to place Data into.

Select if Input to be Byte Swapped.

Select for Checksum Calculation.

Select Checksum Type.

Enter a value for Checksum Result Offset.

Select High-Low or Low-High Order.

Select All Ranges or enter a Byte Range.

Select based on Communicating device documentation.

Select and enter a Value for Fixed Length.

Select and enter a Value for Max Variable Length.

Select for 1Termination Character.

Select for 2 Termination Characters.

Enter a Hexadecimal value.

Enter a Hexadecimal value.

Enter Time in Seconds for First Character Alarm.

Enter Time in Milliseconds for Inter Character Alarm.

Select a Boolean Tag for the In Progress bit status.

Select a Boolean Tag for the Complete bit status.

Select a Boolean Tag for the Success bit status.

Select a Boolean Tag for the Checksum Error Alarm bit status.

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

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

Select a Boolean Tag for the Overflow Alarm bit status.

Enables the use of Structures.