Controls Department

• A virus can destroy the HMI computer's software with typical daily usage or the computer itself could stop running. If this happens it will have no effect on the control computer or multiple control computers running the actual control system software.
• The ability to break a large plant into more manageable sections. For example, one building or twenty zones per control computer; with the accessibility of split system, if one machine crashes only a small section of the overall facility is down. And if a controller fails, a backup system is in place on the HMI computer to run the lost controller's program where it last left off. This is due to a small program that backs up all the data, logs, programs, and user files from each of the controllers to the HMI four times a day. In a worst-case scenario only a few hours may be missing from the data compared to several hours or even days without the split system features.
• We can also split up the communication into separate runs, making it easier to run communication wiring and limit the number of control panels on each line. This saves our customers money and limits the opportunity for system failures and issues.

To expand our customers’ security, we have designed our own backup system separate from HMI. A mechanical form of security that can be engaged in critical situations such as high scale theft and power failures within the computer housing.

We incorporate toggle switches for most of the digital I/O. This gives access to cool any zone without the computer control system running.

Low temperature stats have two basic uses on the system; it can act as a low temperature trip safety when it is in manual operation. The second is to set the stat to go cooler and used as a backup safety to the computer control system.

We also offer pressure switches and micro control panels for compressors and condenser control. For the majority of computer control systems, these are set outside of normal operating values and can be engaged if the control system is down.

We know that there are a number of facility operators that would like the ability to customize their displays. So what we did is give them a system they can be comfortable with by allowing customization of the user interface. Colors, fonts, screen layouts, alarm setup, security and other types of customizable tweaks.

When in editing mode all the items on the screen become movable, re-sizable, and can have any of their individual properties changed.

For example, if you want the dial shown for the BPR motor to be a digital readout, it takes minimal effort to transfer to the digital format. Also while this item is still selected, any of its other properties can be modified as well.

This not only helps legibility but also lets users design ideal layouts to fit their individual needs.

Our staff has decades of combined experience in several different platforms and types of equipment. Because of this we have been able to narrow out products that are ineffective or outdated, giving our customers the most reasonable options to choose from. The computers we use are standard PCs, running the Windows operating system. We have minimum requirements that are inexpensive, well known, and easy to replace locally.

How much impact does this control system have on these computers? With our control system maxed out it uses about 2%-5% of the CPU time running the software. There is a substantial difference between PLCs and the popular canned software systems that are capable of using up to 95% of all system resources leaving no room for any customization to the customer.

When a PLC is developed, PLC proprietary tools are also developed to program it. These specialized tools run on PCs and need PC to upload projects to the PLC. As computers and their operating systems change, outdated PLC tools may no longer be supported.

PLCs tend to only run ladder logic, unfortunately the ladder logic setup for the original PLC is not transferable to another brand/model of PLC. This forces the developer to adapt all prior logic to a different brand of PLC, costing the company time and money in redeveloping and/or retraining their personnel. Another downfall is that all the I/O is built right into the PLC. If a single I/O point burns out, the logic will need to be rerouted to a different point or the whole PLC will need to be replaced depending on the age of the system.

We developed our system with Microsoft's programming language, and we stay current with programming changes. We maintain older versions of our software, and make sure that all our customers will have a direct upgrade path to the latest software version, with little to no downtime. The other benefit is if one I/O point is burned out, one I/O point is replaced, because the I/O is separate from the brains and easily swapped out.

The main I/O hardware we work with is Opto 22. With one hundred percent of their manufacturing being in the United States, Opto 22 still supports some of their oldest equipment. The Opto 22 hardware is extremely reliable and has been proven to survive in harsh conditions.

With the Opto hardware, we have two ways of communication: Serial 422 (multichannel) or TCP/IP. Both communication packages have advantages and disadvantages over one another, leaving it up to the customer to decide what would work best in their facility. We have also built in hardware troubleshooting that allows you to view that communication, I/O points and any errors.

To make any changes in the control program, a person will need to have a user name and password set up on the system. To help facilitate this an administrator for the plant is usually chosen to oversee, add, edit, or remove users from the system.

When any changes are done on the system, or when someone logs in or out, the system keeps track of it by recording the event into a daily log. These can be back tracked up to a year or more and can help someone see when a problem had occurred.

Other events such as computer reboots, errors, and when an alarm clears are all saved in the daily logs.

Due to the backup data system we use, our control division can save all the facility's data into daily encrypted data files. Saving new data in 2-minute intervals 24/7 without any extra adjustments on the customer’s end. For example, there can be over 700 kilobytes of data in a facility with twelve zones, so it's easier to copy to a remote computer for viewing.

To make the data easy and quick to navigate, we developed user configurable scripts in the graphing program. The scripts allows the user to select only the information they are interested in each day and once the script is saved just click on it, select the dates to be viewed and the system will generate a graph and log sheet of all the data associated with that script.

After the data has been generated, the logs can be searched and highlighted. The program can also flag any data that's missing and give a quick report.

Another tool is also available to record custom data that an operator may need, like trying to catch an event that might require someone to sit all day watching. Unlike our standard data this one gives more options for recording interval (1 second to once every 24 hours) and gives you some points not normally found in the regular data list.

You also have the option to save data and view it in an Excel format (no encryption).

Over the years we have worked very closely with energy engineering companies to provide a host of energy savings features for our customers. We have advanced control for compressor trimming, VFD control and monitoring, ideal condensing sequencers, wet bulb algorithms, and power monitoring. We also have some advanced plant cycling to avoid high energy costs during peak hours.

Proactive vs. reactive control for energy savings:

While reactive power monitoring can save money, these type of plans tend to sacrifice the product, and just shut down the whole plant for a given time.

What we do is proactive control. Meaning the plant supervisor can schedule parts of the plant to scale back during known peak times, but the control will still monitor any zones currently off during cycling for high temperature limits and zone to run for a while to keep the product intact. This will have the effect of shedding the load needed to run the plant, so less compressor and condenser will be needed without a complete system shutdown.