Project: Biopharmaceutical filtration automation (November 9, 2005)
November 9, 2005
Project Status Summary:
1. MF software design 100%
2. MF software code complete 100%
3. UF software design 100%
4. UF software code complete 100%
5. HMI software code complete 100%
We have reached initial code completion and are well into beta testing. As normally happens, testing begins slowly and accelerates. This acceleration in testing happens for a few reasons including the following:
Testers require ramp up time to become proficient in the application and to understand what to expect;
Simulation normally needs tweaking to adequately test the application;
Number of code defects decrease over time as they are found and fixed; and
A code defect found in one module is fixed in all modules that use a similar construct. This eliminates defects in modules yet to be tested.
The project now includes the following 7 HMI displays:
Filtrate Hold Vessel
Ultrafiltration (UF) Vessel
Each of the processing units and the basic process flow are shown on a single overview display. Pressure, temperature, and volume are displayed for each tank. The current status for each unit is also displayed with a countdown timer showing how much time remains before the current status expires.
The peer-to-peer display provides status information for messages that are passed between PLC processors for control purposes. This display will prove very helpful when troubleshooting the system. The communications between processors—critical to system operation—would otherwise be a mystery that only a programmer could decipher. With this display, savvy operators, supervisors, and engineers can perform basic diagnostics without asking a control engineer to dig into the running code.
The top area of the display includes a navigation toolbar and the bottom area includes a small active alarm grid. Individual graphic displays reside between these two sections. As users navigate between graphic displays, the toolbar and alarm sections do not change. In fact there is actually a single master HMI graphic with a toolbar on top, alarm banner on bottom, and nothing in the middle. Graphic displays are layered above the master graphic. This design allows us to provide a global alarm and navigation system that can be reused between projects.
The toolbar button labeled Graphics is a drop-down that lists the available graphics on this workstation. The list of graphics shown in this dropdown is defined in an external XML text file that is read by the master graphic when the HMI is loaded. To add another graphic display to the menu requires only the addition of an entry in the text file. The XML entry includes the menu text, the file name of the graphic display to open when the menu item is selected, and security level required by users to access the menu item. We use the same configuration file to define menu items for the Trends button and the Apps button. The Apps button allows the user to access external applications from the HMI. For example, the Apps dropdown may include menu items for RSLogix programming software, RSLinx communications software, and SQL Server Enterprise Manager. Applications such as these will normally be limited to users with advanced security privileges.
Next up, testing, testing, and more testing. Also, there are a few other external applications we provide with our system for managing access to data archives, which are being set up this week and should be completed by my next update.