The Wonderware/InTouch SCADA system, which is connected to the PLC, maintains the database of information relating to the
identity, number, grade, and location of sides in the plant. This computer works in conjunction with the PLC to control the movement of sides throughout the plant in accordance with the operators' wishes. The SCADA interface screens) are also used for status and alarm messages, and for operator acknowledgment of the same.
The primary means of controlling the plant, and for gathering information for operational or maintenance purposes, is via the computer in the tally room. This computer runs the supervisory program, which must be left to run constantly. This program maintains the database of information about the various sides, and allows the operator to view what is going on in the plant and control the movement of the sides.
There are many different screens in the computer system, that correspond to the different sections of the plant. In addition there are menu and navigation screens, as well as a dedicated alarm screen.Database System
The database stores the following information about each side:
the number of the hook that the side is hung on;
the APAS system data for that side;
the grade (taken from APAS) assigned to that side;
the date and time when the side left the kill floor;
the weight of the side prior to entering the chiller area;
the chiller number (once the side reaches its assigned chiller);
the weight of the side exiting the chiller area;
the date and time when the side left the chiller area;
the assigned boning lane number (once the side has exited the chiller area).
The APAS information is transmitted to the computer in the tally room.
The sides are tracked by means of a Radio-Frequency Tag that is mounted in each hook used in the system. Each tag is unique, and is scanned into the system whenever the hook passes in front of any of the scanners that are located throughout the plant. This allows the system to identify exactly which side is passing by a given point at any time, and hence to direct the control of the various sorting and tracking functions in the plant. In addition to these scanners, there are proximity switches located wherever necessary to index and count the sides, and control the various gates and walking beams.
These scanners are connected via a serial link to the computer in the tally room. There are five (5) RF scanners located throughout the plant, in the following locations:
at the exit of the roller cleaning - this scanner simply checks that each tag is scanning correctly (as tag integrity may be compromised due to mechanical abuse). If the tag does not scan, its hook will be rejected so that it will not cause a tracking error in the system;
at the exit of the Kill Floor - this is where the APAS system assigns a grade to each side, and the program assigns that grade to the corresponding hook number in the database, allowing that side to be tracked by grade throughout the rest of the plant;
as the sides approach the Marshalling Area - this is the point at which the sequence of graded sides is used to assign grade values to different lanes in the marshalling area, and to direct the individual sides to the correct lanes;
As the Sides enter the Chiller corridor - this scanner checks the grading of the sides as they travel to their destination chillers, to ensure that the correct grades are allocated to the requested
At the Chiller outlet - this scanner is located near the check scale, and provides confirmation of the grade of side being moved out to the boning chains.