Level 1.5 Systems

The Operator Interface

A well-designed operator control station makes the operator an integral part of the control system. With information at his fingertips and controls strategically placed, he is able to monitor and control the process in an efficient and effective manner.

As changes are made, equipment is added, and the process becomes more complex, the operator still must maintain his role as an integral part of the control strategy. Also, given the tendency toward downsizing through automation and consolidation of functions, the operator has an even greater reliance on a well-designed control station.

The tendency today is to use computer display screens that mimic the operator stations. Using multiple interactive screens to move between functions and display information, the operator has more control at his fingertips than ever before. Operator initiated functions through touch panel screens or keyboards are passed to the control devices within fractions of a second. Feedback information about a device or sequence is passed back to the display screen with the same speed. In fact, a single operator’s station with a few display screens, keyboards or touch panels can replace entire desk or panel line-up, common in the mills a few years ago, without the expense of hardwiring and cabling.

The design of the operator’s station must be done properly, otherwise it becomes cumbersome and the operator becomes disenchanted with the improvement. Often referred to as Human Machine Interfaces (HMI) or Operator Interfaces (OI), highly functional and ergonomic designs, with operator input, are necessary to achieving success.

IPACT has experience with designing and building both new and replacement HMI systems for a variety of industries. Having worked with several of the more popular system software suppliers, we can integrate industrial duty personal computers with network servers to create large or small operating stations. Communicating over high-speed and low cost Ethernet cabling (10 Megabits per second), information is quickly exchanged between points or nodes on the network. Control functions are carried out promptly and information is readily available. Relational databases within the network servers provide methods of organizing and retrieving information. More importantly, the system easily expandable by the customer should future needs arise.

And just because it’s a computer system performing control functions, one need not be concerned about down time in the event of a computer failure. Each PC can perform the function of its neighbor. Critical areas will have at least two PCs to create an on-line back up. The network server can also be redundant, providing a "hot backup" concept. Many customers choose to use the backup as a development tool, allowing them to develop additional screens and displays on their own.

The placement of the Level 1.5 in the system does not restrict its usage only to Level 1 applications. The HMI can literally be a window into any part of the mill’s computer system. The flexibility of the design allows for data and control functions to be initiated in Level 2 and the display of such information on any of the operator’s screens. This truly gives the operator access to a wealth of information.

IPACT’s philosophy for design involves operating and mill personnel. We start with a thorough understanding of the application, usually depicted through the application of sequential function charts. We ask for area operator representation to enhance our understanding, before proceeding with the design. Mid-way through the design, we have a design review with operators and mill personnel, and repeat this process at the end of the design phase. This process ensures that the HMI system will serve the needs of the mill and the operator and gives the operator a sense of ownership, an ingredient crucial to operator acceptance.

The Maintenance Employee

Just as important from a maintenance standpoint, the HMI is becoming an ever-increasing tool for the mill mechanic, electrician, or instrument technician. Today’s sophisticated digital drive systems, instrumentation systems, and mill diagnostic equipment can be connected directly to the Level 1 network or into the Level 2 systems. Containing a wealth of maintenance information, these computer or microprocessor-based devices can provide this data to the HMI system. Custom designed maintenance screens can be used to remotely troubleshoot or data trend mill equipment in response to alarms. Often this information can be downloaded to maintenance diagnostic software to help predict a deteriorating machinery condition, allowing repairs to be scheduled before a breakdown occurs.

Integrated Process Automation & Control Technologies