Electronic circuit for a field device used in automation technology

An electronic circuit for a field device of automation technology, comprising:

• a first digital processor having a first set of machine commands adapted for executing a measured value algorithm running in the first processor for calculating a digital measured value based on a raw measured value, wherein the first processor uses at least a part of the first set of machine commands for executing the algorithm, wherein the first processor is further adapted to execute a test algorithm to calculate an output data based on an input data, wherein the test algorithm is divided at least into a start section and an end section and the first processor is further adapted to execute at least a part of the measured value algorithm between the start section and the end section of the test algorithm, wherein the test algorithm uses for calculating the output data at least a part of the first set of machine commands which are used for executing the measured value algorithm;
• and
• a second digital processor having a second set of machine commands for executing a verification algorithm, wherein the second processor is fed the input data and the output data of the first processor and the second processor is adapted to execute the verification algorithm to calculate verification data based on the fed input data, wherein the verification algorithm uses for calculating the verification data machine commands of the second set corresponding to at least a part of the first set of machine commands which are used for executing the measured value algorithm, wherein the verification algorithm is permanently coded in the second processor so that the verification algorithm does not have to be written into the second processor upon starting the field device,
• wherein the electronic circuit including the second processor is adapted, based on the output data calculated by the first processor and the verification data calculated by the second processor, to perform a checking of the first processor.

A method for cyclically checking a first digital processor having a first set of machine commands by a second digital processor having a second set of machine commands, the method comprising:

• executing cyclically a measured value algorithm for calculating a measured value in the first processor, wherein at least a part of the first set of machine commands of the first processor is used for the executing;
• executing cyclically in the first processor a test algorithm subdivided into at least a start section and an end section, wherein at least a part of the measured value algorithm is executed by the first processor between the start section and the end section of the test algorithm, wherein the test algorithm calculates output data based on input data, wherein at least a part of the first set of machine commands which are used for executing the measured value algorithm is used for calculating the output data;
• executing cyclically a verification algorithm in the second processor, wherein verification data are calculated by the verification algorithm based on the input data, wherein for calculating the verification data machine commands of the second set are used, which correspond to at least a part of the first set of machine commands which are used for executing the measured value algorithm, wherein the verification algorithm is permanently coded in the second processor, so that the verification algorithm does not have to be written into the second processor upon the starting the field device;
• and
• checking cyclically the first processor based on the output data calculated by the first processor and the verification data calculated by the second processor.