"Over a couple of years, L&S kept coming up with slight changes to its wash bay program, which required altering the PLC program, but they didn't have a staff engineer to do it every time someone wished to try something different," explains Itell. "However, L&S was very comfortable with Microsoft Access, so we needed a way for L&S to use Access to generate programs that could be executed in the PLC."
After examining the wash bay application more closely, L&S and Cemtech decided it fit the description of a sequential batch application because it also has steps that that were executed based on a time or an event. "All that was needed was a way to send a request written in Access to the PLC," explains Itell. "This was done with a Visual Basic (VB) macro in the GraphworX software. Iconics makes it easy to write VB modules that integrate with the HMI."
Consequently, Access was used to create the sequential batch program by first entering segment times, output states, inputs and logical events into a software table, and saving these entries as a unique database with a folder on the operators' computer. They can then select from all programs in that folder which program they wish to download to the FA-M3 system. Once downloaded, the program will be executed until a different program is downloaded.
Also, when a wash cycle is finished, a wash ticket is generated. This records completed washes and serves as a record for billing. GraphworX's HMI also generates a circular chart showing a trend of the supply and return temperatures to provide proof of sanitization of the tank.
"Now we can do it ourselves. We can add CIP recipe changes right on the PC in the Microsoft Access database, rather than calling our Yokogawa rep every time we need to change our software programming," explains Widrick. "For example, we can do a separate CIP program for heavy corn syrup that extends the pre-wash stage.
Previously, we had to do two full washes, so just extending the pre-wash saves a lot of water, energy and time."
Gains Secured, More Coming
The first major improvement that L&S gained by using FA-M3, GraphworX, Microsoft Access and its sequential batch program was that individual tank wash cycle times were reduced to about 40 minutes per trailer, so it can now complete 10 to 20 wash cycles per day. In fact, cutting wash times by 50% saved about eight hours per day, or a whole shift, in labor costs.
Besides saving time, L&S also learned that its FA-M3 and GraphworX system could help it save energy, too. For example, L&S uses its flexible CIP programs to adjust boiler performance. "We used to keep the boiler running for a whole 15-minute cycle, but the trailer tanks are well insulated and retain heat. So we realized we could maintain the required water temperature, but use the CIP program to turn off the boiler 10 minutes earlier than before, and save about 33% on our energy costs," adds Widrick. "Because we could play with the software and see how our process was working, we also found that we only needed 10 in. of water in the tanks, instead of 40 in., and this is saving a lot more water and energy."
Because of its success in the wash bay area, L&S is looking at using its sequential batch program in its blending department to help automate its sugar blending application.