Product : ISaGRAF V3
Date : 8-March-1996
File : Ioscan.ios scanning and oem call description.htm
Subject : IO scanning and OEM call description
Keywords: I/O driver - Lock - Unlock - OEM call - Virtual
One ISaGRAF cycle is composed of following steps:
Mainly, OEM programmer function reads input devices values and writes them into inputs database (iovar->data is used and directly handles on ISaGRAF database).
Input lock test must be taken into account by the OEM programmer
Before conversion, input data base value is temporary incorrect
Even for real iovars, OEM programmer generally writes only integer values. Therefore, even if there is no conversion to be applied, an automatic conversion is performed to cast integers into real values. (If the OEM programmer writes a real value he must define the DEF_IOS_REAL option).
Mainly, OEM programmer function reads output data base value and writes it into the output device (iova ->data is used and directly handles on ISaGRAF database).
OTHER IOs ACCESS:
Copyright © 1996-2009 ICS Triplex ISaGRAF Inc. All rights reserved.