M-b-319 - Programmable Logic Controller System, etc.
200 C Street, S.W.
Washington, DC 20204
May 1, 1993
TO: All Regional Food and Drug Directors
Attn: Regional Milk Specialists
FROM: Milk Safety Branch (HFF-626)
SUBJECT: Programmable Logic Controller System for Flow Diversion Devices from Custom Control Products, Inc. (Models 5055P, 5057P, 5065P, 5067P, 5075P, 5077P)
FDA has completed the review of a proposed control panel system for flow diversion devices submitted by Custom Control Products, Inc., Racine, Wisconsin. The firm proposes to enhance the previously reviewed programmable logic controller (Allen Bradley SLC 100) which can currently be used with all approved flow diversion devices (M-b-313 and M-b-313 Supplement 1). The enhanced system would be based on the Allen Bradley SLC 500. The different model numbers indicated the type of enclosure and whether or not solenoids are included with this controller (for use with or without valves without built in solenoids). Stainless steel enclosures are model numbers 5055P (without solenoids) or 5057P (with solenoids). Fiberglass with clear front enclosures are model numbers 5065P (without solenoids) or 5067P (with solenoids). The all fiberglass enclosures are model numbers 5077P (without solenoids) or 5075P (with solenoids). Both fiberglass enclosures are designed for installation inside a larger stainless steel cabinet or control area.
When the Allen Bradley SLC 500 is programmed as shown in the attached ladder logic diagrams, the system complies with the intent of the Grade "A" Pasteurized Milk Ordinance and Coded Memo M-I-88-11 regarding the use of computerized systems for public health controls on HTST pasteurizers. The hard-wiring to the input board of the control system will vary slightly depending on which approved flow diversion device is used with the SLC 500. Input hard wiring for all FDA reviewed flow diversion devices required for this control system is also attached to this memorandum. The cognizant health authority shall retain a copy of these ladder logic diagrams and the hard-wiring to the input board for the appropriate flow diversion device for the office record.
Any flow diversion device utilizing the Custom Controls Products, Inc. system shall pass all tests in the Grade "A" Pasteurized Milk Ordinance for dual-stem flow diversion devices. With respect to the requirements of Item 17 in the Coded Memo M-I-88-11, the device panel box with the solenoids and the SLC 500 will have provision for an inspector's seal. In addition, the SLC 500 will have a plastic plate with provision for an inspector's seal which denies access to the programming port and EEPROM memory card. The EEPROM memory card supplied by the firm has been permanently modified so that it cannot be reprogrammed. Finally the firm will place its own trademark on the inside of each EEPROM memory card. If the cognizant health authority has any questions concerning the program in the SLC 500, the memory card may be pulled from the SLC 500 to check for distinguishing trademark.
The enclosed electrical drawings are from Custom Control Products, Inc. and the ladderline logic is provided by the All-Bradley Company. Also enclosed is a permission to duplicate both documents for official regulatory use.
States desiring further information or copies of the literature enclosed may contact:
Custom Control Products, Inc.
1300 North Memorial Drive
Racine, Wisconsin 53404
Sufficient copies of this memorandum are enclosed for distribution to state milk control agencies and State Milk Sanitation rating Officers in your region/district.
FDA's review of this dairy equipment and our finding that they comply with the applicable construction criteria of the Grade "A" Pasteurized Milk Ordinance does not constitute agency endorsement or approval of the dairy equipment and any representation on a label or in any printed literature that they are "FDA approved" would be false.
Steven T. Sims
Senior Milk Sanitation Officer