Field Device Memory Segmentation for Extended Service Life
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Field devices in process automation face limited power supply due to explosion protection specifications, leading to the need for EEPROM-based data memory with limited write cycles, which results in a short service life, especially in applications with high data turnover and volume.
Innovation Solution
A field device with a centralized data processing unit, a buffer memory unit capable of 106 write cycles for temporary storage, and a long-term memory unit for less frequent writes, allowing data to be copied from the buffer to the long-term memory when a defined volume or time is reached, thereby extending the device's operational readiness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If EEPROM-based data memory is used to store device-related data, then the field device meets explosion protection specifications and has low power consumption, but the limited number of write cycles (10^4 to 10^5) results in short service life
Solution Approach 1:
The data memory is segmented into two distinct parts: a first data memory (EEPROM) with limited write cycles for storing critical device-related data, and a second data memory (FRAM) with high write cycle capacity for storing dynamic process data. This segmentation allows each memory type to be optimized for its specific function, resolving the contradiction between low power consumption and long service life.
Solution Approach 2:
The system changes the storage parameters by selectively storing different types of data in different memory media based on their characteristics. Static or infrequently changing device data is stored in EEPROM, while dynamic process data requiring frequent updates is stored in FRAM, thereby optimizing both power consumption and service life.
2Reliability
If FRAM-based data memory is used instead of EEPROM, then the write cycle capacity increases to 10^6 to 10^14 cycles extending service life, but the cost per memory capacity becomes disproportionately higher
Solution Approach 1:
The data memory is segmented into two distinct parts: a first data memory (EEPROM) with limited write cycles for storing critical device-related data, and a second data memory (FRAM) with high write cycle capacity for storing dynamic process data. This segmentation allows each memory type to be optimized for its specific function, resolving the contradiction between low power consumption and long service life.
Solution Approach 2:
Different memory technologies are applied locally to different data storage requirements. EEPROM is used where low cost and low power consumption are critical, while FRAM is used where high write cycle capacity is needed. This local differentiation optimizes the overall system by matching memory characteristics to specific functional requirements rather than using a single memory type throughout.
3Loss of information
If dynamic device-related data is stored continuously in EEPROM, then real-time data availability is maintained, but the high data turnover rate exhausts the limited write cycles prematurely
Solution Approach 1:
The data memory is segmented into two distinct parts: a first data memory (EEPROM) with limited write cycles for storing critical device-related data, and a second data memory (FRAM) with high write cycle capacity for storing dynamic process data. This segmentation allows each memory type to be optimized for its specific function, resolving the contradiction between low power consumption and long service life.
Solution Approach 2:
The system applies partial action by storing only the necessary data in each memory type according to its characteristics. Critical device data is stored in EEPROM, while dynamic process data is stored in FRAM, avoiding unnecessary write cycles in EEPROM and preserving its limited write capacity for essential data.
Data Source
AI summary
A field device in which device-related data are intelligently stored such that the lifetime of the memory unit and thus the possible service life of the field device is increased initially buffer-stores the generated data in a FRAM-based buffer memory unit and then stores them as a common data packet in an EEPROM-based long-term memory unit as soon as the device-related data have reached a defined data volume in the buffer memory unit. Collecting the data beforehand and then copying the resulting data packet to the long-term memory unit in the form of a common dataset reduces the write cycles to the EEPROM memory, as a result of which the lifetime of the EEPROM memory is lengthened. It is not necessary to retain any large FRAM-based data memory, making it possible to keep memory space costs for the field device low.