Applies To:
  • CitectSCADA 4.20

Summary:
Does Citect support unsigned integers? 

Solution:
Citect normally treats 16 bit integer from IO devices as a signed value between -32768 to +32767.

The two exceptions, so far are the COMLI and MODCELL protocol, which treats all its 16 bit integer as an unsigned value between 0 to 65535. These protocols have their 0x800 option set in the protdir.dbf, which tells the Citect compiler to generate code to treat all 16 bit integer from these protocols as unsigned values. If the user use tags from these protocol on a Super Genie, they will be treated as signed values because the compiler does not know what protocol will be used at run time.

Two Citect ini variables have been added to temporary fix this problem.

[Code]
Unsigned=0

Set to 1 to treat all 16 bit integers from COMLI and MODCELL I/O devices as unsigned.

[PROTOCOL]
Unsigned=0

Set to 1 to treat all 16 bit integers from "PROTOCOL" I/O devices as unsigned. [Code]Unsigned must also be set to 1.

These fixed will be available in Version 4.20 Service Pack C.

 

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