Methods and structures for utilizing a memory device for a PLC
AssigneeSiemens Industry, Inc.
InventorsTemple Fulton, Mark Boggs, Steven Hausman, William Johnson
Life of this patent
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Abstract
Certain exemplary embodiments comprise a method comprising a plurality of activities comprising: at a programmable logic controller comprising a memory device, receiving a request to create a data log that is adapted to receive data from a process; initializing the data log by writing to the data log a head marker code in the record type field of a first record and an invalid code in the record type field of a last record of the data log, the last record logically preceding and logically adjacent to the first record.
Claims22
A method comprising a plurality of activities comprising:
- at a programmable logic controller comprising a memory device, receiving a request to create a data log comprising a predetermined plurality of records, the data log adapted to receive data from a process, each record comprising a record type field;
- initializing the data log by only writing to the data log a head marker code in the record type field of a first record and an invalid code in the record type field of a last record of the predetermined plurality of records, the last record logically preceding and adjacent to the first record;
- and
- automatically invalidating the first record.
A method comprising a plurality of activities comprising:
- at a programmable logic controller comprising a memory cartridge, determining that the memory device organization is not known by the programmable logic controller;
- locating a data log on the memory device, the data log comprising a predetermined plurality of records, each record comprising a record type field;
- locating a head marker code in the record type field of at least one of the predetermined plurality of records;
- if more than one head marker code is found in the predetermined plurality of records, finding a logically first record comprising the head marker code, wherein the logically first record is a next record to be populated with process data;
- and
- automatically invalidating the logically first record.
A machine readable medium comprising stored instructions for:
- at a programmable logic controller comprising a memory device, receiving a request to create a data log comprising a predetermined plurality of records, the data log adapted to receive data from a process, each record comprising a record type field;
- initializing the data log by only writing to the data log a head marker code in the record type field of a first record of the predetermined plurality of records and an invalid code in the record type field of a last record of the predetermined plurality of records;
- and
- automatically invalidating the first record.
A machine readable medium comprising stored instructions for:
- at a programmable logic controller comprising a memory cartridge, determining that the memory device organization is not known by the programmable logic controller;
- locating a data log on the memory device, the data log comprising a predetermined plurality of records, each record comprising a record type field;
- locating a head marker code in the record type field of at least one of the predetermined plurality of records;
- if more than one head marker code is found in the predetermined plurality of records, finding a logically first record comprising the head marker code, wherein the logically first record is a next record to be populated with process data;
- and
- automatically invalidating the logically first record.
A machine-readable data structure encoded on a machine-readable medium, the machine-readable data structure comprising:
- a process-data receiving data log of a programmable logic controller, the data log comprising a predetermined plurality of records, each record comprising a record type field, wherein the record type field for at least one record comprises an automatically record-invalidating head marker code.
Dependencies are inferred from the claim text.