Serial F-RAM remembers pressure transmitters

F-RAM device stores configurable parameters such as transmitter ranges, signal types, fluid properties etc, and retains the data when power is removed.

China's Shanghai Welltech Automation, a leading pressure transmitter and magnetic flow meter supplier, has designed Ramtron's FM25L16 16Kbit serial F-RAM device into its 2000S safe pressure transmitters.

F-RAM was selected to replace EEPROM in Welltech's new intrinsically safe explosion-proof transmitters.

Intelligent pressure transmitters have become increasingly popular because of the complexity of today's process control applications in industries such as chemicals, pharmaceuticals, power, water treatment, food processing etc.

The 2000S offers advanced features such as two-way communication, remote calibration and self-diagnostics.

These features enable higher accuracy, greater reliability, and more advanced communication protocols, which reduce the time, effort and expenses associated with start-up and maintenance.

The 2000S combines sensing technology and intelligent electronics in a single package.

Nonvolatile F-RAM - with its fast writes, high endurance, and low power - is an integral element in this advanced design.

In the 2000S, F-RAM stores configurable parameters such as transmitter ranges, signal types, fluid properties etc, and retains its data when power is removed so that the transmitter is ready for immediate use when power is restored.

F-RAM also saves calibration/compensation data for the 2000S's automatic self-calibration routines, and performs event and data logging, which the system uses to diagnose whether maintenance is required.

"We have replaced EEPROM with F-RAM in our smart and safe 2000S pressure transmitters to extend write speed and endurance, and to improve overall safety against potential explosions", explain Welltech R and D Engineers.

"We used EEPROM in our first 2000S designs, but it failed in power consumption tests since the 2000S has a total operating current of less than 3.6mA.

F-RAM's low power consumption enables intrinsic safety, while its fast writes reduce variability and microprocessor (MPU) overhead in our new smart pressure transmitters".

The 2000S is "intrinsically safe".

This means it is designed to prevent the release of energy that can cause the ignition of flammable material and cause an explosion.

As such, it requires a memory device such as F-RAM that has very low operating currents.

F-RAM's fast writes are integral to reducing variability in computing process measurements.

This produces more accurate measurements for self-diagnostics, greater system control, and improved profitability.

The 2000S includes an MPU for complex calculations.

As the processing becomes more intensive in intelligent pressure transmitter applications, F-RAM's fast write advantage alleviates MPU overhead.

F-RAM memory offers the benefits of RAM technology, but is nonvolatile.

F-RAM provides NoDelay write access, virtually unlimited write endurance (approximately 1e14 write cycles), and low power consumption.

The FM25L16 is a 16Kbit F-RAM device with an industry-standard serial peripheral interface (SPI).

The device reads and writes continuously at bus speeds up to 18MHz and low operating currents.

Comparable EEPROM devices have long write delays and write-polling software, endurance limited to less than one million write cycles, and operate at higher power.

Available in lead-free, 8-pin SOIC and DFN packages, the FM25L16 operates at 3V over the industrial temperature range.

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