Setting possibilities in the registry and TwinCAT PLC Control.ini
The settings for data transmission via remote access are made in the registry and in the TwinCAT PLC Control.ini file.
In the case of analogue modem connections with low transmission rates or poor cable quality, it may be useful to reduce the size of the data blocks to be transmitted.
If it is intended to transmit a PLC project from the TwinCAT PLC Control to the controller per ADS via the modem connection, the size of the data blocks can be changed by means of the following settings:
Registry
MaxBlockSize
HKEY_LOCAL_MACHINE\SOFTWARE\BECKHOFF\TwinCAT\Plc MaxBlockSize (DWORD)
By default, the size of the packet is assumed to be 16 KB (even if there is no key in the registry). The smallest block size is 512 bytes.
This means that large PLC projects to be loaded are subdivided into blocks.
Smaller block sizes should be configured if the connection is slow.
ConnectionTimeoutMSec
HKEY_LOCAL_MACHINE\SOFTWARE\BECKHOFF\TwinCAT\Plc ConnectionTimeoutMSec (DWORD)
The default value is decimal 8000 (= 8 seconds)
This value should be increased if the connection is slow.
TwinCAT PLC Control.ini
The file "TwinCAT PLC Control.ini" exists in the directory "..\TwinCAT\PLC"
[TwinCAT PLC Control]
FileTransferBlockSize=16384
The default value (even if there is no key in the INI file) is 1024; 16K is usually set in the case of a CX9000 to minimize the number of blocks.