[PLC4X-133] ADS Big-Endian Support

• Type: New Feature
• Status: Open
• Priority: Minor
• Resolution: Unresolved
• Affects Version/s: 0.4.0
• Component/s: Driver-ADS
• Environment: Client ; - JDK 8 ; - Windows 10 ; - TwinCAT3 v3.1.4022.29 ; ; PLC ; - Beckhoff IPC C6920-0030 ; - Intel Core 2 Duo mit Windows 7 64Bit ; - Twincat XAE 3.1.4022.29 (64Bit Runtime)
• Assignee: Unassigned
• Reporter: Martin Illecker
• Created: 04/Jul/19 12:23
• Updated: 09/Nov/22 10:14

Description

For some reason the response of the PLC seems not to be in LITTLE_ENDIAN format.
Therefore, the Byte to Integer conversion in [1] results in a negative number.
 
The issue occurs during the symbolHandle creation process in [2].
 
I had a look at the ADS specification [3] and the response should be in LITTLE_ENDIAN format, but for some reason it is not.
 
As suggested by Christofer Dutz we should create an option to override the endianness in the connection-string.
 
[1] https://github.com/apache/plc4x/blob/develop/plc4j/protocols/ads/src/main/java/org/apache/plc4x/java/ads/api/util/UnsignedIntLEByteValue.java#L39
[2] https://github.com/apache/plc4x/blob/develop/plc4j/drivers/ads/src/main/java/org/apache/plc4x/java/ads/connection/AdsAbstractPlcConnection.java#L187
[3] https://infosys.beckhoff.com/index.php?content=../content/1031/tcplclibutilities/html/TcPlcLibUtilities_AddOn_ByteOrder.htm&id=