Dynamic Data Exchange

Software programs are available to accept data from instruments and transfer it in real time to Excel. For example, SoftwareWedge (TAL Technologies, Inc., 2027 Wallace St., Philadelphia PA 19130) captures RS-232 serial I/O data, parses and filters it to user specifications, and transfers it to Excel for Windows via DDE (Dynamic Data Exchange). Data can be received from several serial ports simultaneously. The user can also define output strings, which can be sent to an instrument to control it directly from Excel. Discussion of this and similar software is beyond the scope of this book specific information can be obtained from the manufacturer. 

Data can be embedded with their original application using ActiveX, Object Linking and Embedding (OLE), or Dynamic Data Exchange technologies. 

Virtual instruments such as these are not only useful with respect to modeling and forecasting, but perhaps more importantly, they become a knowledgebase in which interventions and the efficacy of these interventions can be statistically proven. In addition, virtual instruments can employ standard technologies such as Dynamic Data Exchange (DDE), ActiveX, or TCP/IP to transfer data to commonly used software applications such as Microsoft Access or Microsoft Excel . In this way, virtual instruments can measure and graph multiple signals while at the same time send these data to another application which could reside on the network or across the Internet. 

The interface between the DCS and Systeml server (rules engine) uses the Dynamic Data Exchange (DDE) protocol. On the other hand, the interface between the rules engine and the Mark V as well as that between the rules engine and the monitoring server uses OPC (Open Process Control) whieh is based on a server-client architecture protocol. The rules engine can also interact with input files via API (Application Programming Interface) to read manually input data that is not available from either the Mark V or DCS. 

We have to mention that the starting data set (Table 4.1) is rather large therefore, it was prepared first as an Excel table and loaded into Mathcad environment using dynamic data exchange tools (Fig. 4.1 shows only a part of the... 

Each GUI has its own standards for interapplication data exchange. Popular examples are today Dynamic Data Exchange (DDE) in Microsoft Windows, Inter-Apphcation Communication (LAC) in the upcoming version 7 of the Apple Macintosh operating system, and AppUcation Communication Services (ACS) on the Digital platforms under DECWindows. 

The experimental data conformed to Eq. (93) and therefore could be interpreted by either mechanism I or II data analysis showed no linear dependence of the logarithm of parameter C in Eq. (93).on the carbon number of the alkyl sulfate hetaerons. However, in the case of dynamic ion exchange parameter C is the binding constant of the hetaeron to the stationary phase hnd its logarithm should be linearly dependent on the carbon number of the alkyl moiety. Even if the results of this study are not accepted as support for ion-pairing (mechanism I) uniquely, they cannot be used to validate dynamic ion-exchange (mechanism II) either. 

A particularly compelling argument for dynamic ion-exchange has put forward the observation that retention of anionic and cationic sample components increases and decreases with increasing concentration of a cationic hetaeron, respectively. Whereas anionic hetaerons are expected to promote the elution of anionic eluites and to enhance the retention of cationic eluites, the quantitative data presented in this regard (226) are not wholly consistent with the model since the hetaeron concentration at which the effect is half-maximal is different for anionic and cationic eluites. If the observed phenomena were due to the presence of bound hetaeron in both cases, the two effects would have identical dependence on the hetaeron concentration in the mobile phase. 

The characteristic structural data such as ion-ligand distances and coordination numbers and dynamical data, in particular ligand MRTs, number of needed exchange attempts, and force constants for the ion-water stretching vibration are collected for all cations discussed in Tables I and II, respectively. 

There are three popular hypotheses. Two models propose extreme situations and each encompasses a substantial amount of chromatographic data. These two proposals are the ion-pair model and the dynamic ion-exchange model. The third view, which is broader in scope than the previous two concepts, accommodates both the extreme views without combining the two models. This proposal is the ion-interaction model. 

If one assumes the dynamic ion-exchange model, then equation (3.26) is obtained, which is identical in form to equation (3.24), demonstrating that retention data alone cannot distinguish these two models of retention and that more detailed studies are necessary (Horvath et al., 1977b). 

The process control system includes almost all refinery plants, covering not only the process plants but also tankage, pipeline supervision and effluent treatment. The POX/methanol complex and the loading facilities are, however not included in the system. The dispatch computer has been tailored to the details and requirements of the loading operation. The POX/methanol complex is equipped with its own system that is linked with the refinery control room for the purpose of data exchange. Similarly, the refinery power station exchanges data with the refinery control room in order to match the dynamics of supply and demand. 

---