Applies To:
  • CitectSCADA 4.20, 5.xx

In pre 2.03 versions of the MODBUS driver BCD values were not written correctly. The bug result in the digits in a BCD being swapped so that the value 1234 would be written as 3412. The problem was corrected in version 2.03 of the following drivers: MODBUS, MBPLUS, MODBUSA, MODCELL and MOORE.

In order to facilitate compatibility with existing projects a new Citect.ini parameter has been added. 

The parameter is "SendBCDSwap" the default value is 1. Setting it to 0 will emulate the action of the previous versions of the driver.

For example adding the following to the Citect.ini file will result in BCD values being written incorrectly.