Applies To:
  • CitectSCADA 4.10

Question: Does the 32 bit version of Citect run faster than 16 bit Citect version? 

The simple answer is most likely no. You will not notice much difference between the performance of Citect 16 bit verses Citect 32 bit. The 16 bit version of Citect has always delivered high performance due to the architecture of Citect. This architecture works around most limitations of the 16 bit Windows environment. Microsoft has fixed most of the limitations of Windows 3.x in Windows 95 and Windows NT, so now Citect can rely on Windows to do these functions. Also most Citect projects performance are highly dependent on the response from the I/O devices. So increasing the performance of the CPU and operating system does not greatly improve the performance of these projects. Citect still has to wait for the slow PLC to get the data.

What about all that multi thread support ?

The multi thread support does make Citect more responsive to requests when Citect is performing slow I/O bound operations. For example sending data to a printer. When Citect sends data to a printer under Windows 3.x, you may see slight delays in system response (only in the order of 50-100 ms) in some tasks, e.g. pressing a button. This does not delay protocol drivers which are running under interrupt, as they will pre-empt the printing even under Windows 3.x. Under Windows 95 and Windows NT you will not see these delays. So there is some improvement here, however the effect is slight.