Applies To:
  • CitectSCADA 3.xx, 4.xx, 5.xx

When you have more than 512 I/O Devices in a Citect database then a hardware alarm for an I/O Device may be reported as being for another I/O Device.  Also ErrSetHw/ErrGetHw will not work correctly when there are more than 511 I/O Devices in the database.  To correct this the mask for I/O Devices passed into this function (i.e.. the number added to the I/O Device number) has been changed from 512 to 8192.  The old mask of 512 can still be used by setting



in your configuration file. However with backward compatible mode you will only be able to have ErrSetHw/ErrGetHw work correctlty with 511 IODevices or less in your database.


CIT has confirmed this to be a problem in Citect for Windows versions 3.XX to 5.XX. This problem has been fixed in version 5.21 Service Pack A.