Plant Information Systems

Traditionally in many manufacturing facilities, there has been an enormous gap between the plant floor and the plant MIS system.  Information systems engineers do not have the background or tools to go mining for data in the plant automation systems (typically PLCs), while plant engineers and technicians had neither the time nor the tools to “push” plant floor data up to the ladder in a format which could be digested by the MIS.  Work-around solutions, such as having MIS terminals on the plant floor that the operators would “backflush” information into (e.g. “I made 26 of recipe A and 12 of recipe B this shift”) have been put in place in many plants, but they remain that: work-arounds.  Because IPACT has expertise that covers the spectrum from the plant floor to plant information systems, we have engineered a general-purpose solution to this problem that can be tailored to the existing equipment infrastructure and needs of almost any manufacturing facility, while requiring at most one additional garden-variety PC to be added to the plant automation network.

IPACT has designed and developed a standard approach for the buffering of production and process downtime data in PLCs and collection of that data into an intermediate computer system (Data Collection and Forwarding System or DCFS), in order to subsequently make that data available to the plant MIS computer system in the format “native” to that MIS system.  If there is no existing plant MIS system, the DCFS system can be used to store, recall, and view the data itself.  The system design has been applied to multiple PLC manufacturers and MIS systems.

Two important features were included in this design: the ability to ride through a temporary loss of the DCFS system or the plant network, and interlocking between the PLC buffer and the DCFS that guaranteed one and only one read of each piece of production data by the DCFS.  Ride through time can be designed to meet specific needs and can vary from 30 minutes to several days.  During the ride through time, as long as the PLC controlling the process is functioning, no data is lost.  Ride through and interlocking have been extensively tested both in test set-ups and in the field; no data has ever been lost or repeated.  PLC buffering/interlocking was also designed for minimal loading on the PLC LAN, i.e. only a small number of registers is accessed by the DCFS from each PLC.

Once read from the PLC buffers, the DCFS then does some pre-processing on the data (e.g. units conversion), and stores it in a local ODBC database (usually MS-SQL or ORACLE) to await transmission to the plant’s MIS computer system.  This approach adds a huge amount of additional ride through time for outages of the MIS computer system, its databases, or its networks.  The amount of ride through time is only limited by how much the customer would want to try to “catch up” into the MIS system, and the speed at which records can be processed into the MIS system.  Records are always processed and sent in strict first-in-first-out order both from the PLCs to the DCFS and from the DCFS to the MIS system, so that the MIS system will not become “confused” if tracking product through the plant.

The design works equally well with most common MIS systems, including MANMAN and SAP.

Source and destination codes, part numbers, transaction types, etc. have all been designed in to the system so that the MIS system will receive data in the form it is expecting it.  The DCFS system is very flexible in the method for getting information to the MIS system.  For example, it can make inserts into an ODBC database table (also using an IPACT-developed guaranteed messaging product), or prepare a flat file to be read by the MIS system, both of which have already been done in practice.

The system to this point has been used for reporting production data, tracking product and inventory through plants, and reporting process downtime and reasons.  The production and product tracking functions are completely automatic, and the process downtime reporting can either function completely automatically (e.g. reporting alarm code and time down or time running slow), semi-automatically giving the operator the opportunity to add comments, or manually forcing the operator to add comments or select reason codes, etc.

This design was initially installed for one plant of a large food manufacturer, and has since been adopted company-wide, and IPACT has already installed it at several sites and is in the process of installing it at others.  For this manufacturer the data is fed from the DCFS system up to the plant MIS system.

A system is also now in the process of being installed for a small manufacturer of office products.  In this case, the DCFS is not moving the data to a plant MIS system, but keeping it in an ORACLE database for later retrieval by plant personnel.

Integrated Process Automation & Control Technologies