11. Hardware Expectations

The GEISA specification is written to align with the hardware already in use by platform vendors serving electric utilities. This version of the specification refers to hardware expectations, rather than hardware requirements, because it does not require binary compatibility. [1] Neverthless, it is important to define the expected hardware deployment platform, as it informs a variety of design decisions.

A full GEISA conformant platform, including ADM, API, and LEE or VEE interoperability conformance, should be realizable on:

• ARMv7 CPU with NEON extensions

• 512 MB of RAM

• 1 GB of Flash

• One (or more) network interfaces

• One (or more) metrology interfaces

Note

For the LEE, as this version of the specification does not require binary compatibility, but is limited to source-code compatibility only for LEE GEISA applications, platform implementers MAY choose to use alternate CPUs and/or fewer resources for the LEE.

Platform implementers should be aware that:

• It MAY NOT be possible to implement a fully conformant (ADM, API, and EE) platform on a device with fewer resources

• If GEISA is extended to include binary compatibility in the future, alternate architectures will likely create additional management work for end users (VEE GEISA applications are agnostic to underlying CPU architecture, but are source-code compatible only in GEISA 1.0.)

The vision is that the GEISA EE runs on a wide range of hardware platforms with various capabilities:

• Device types such as smart meters, load switches, EV chargers, etc.

• Single and multi-core CPUs

• Support for processor extensions and coprocessors such as GPUs

• RAM sizes greater than the minimum 512MB target

• Storage sizes greater than the minimum 1 GB target

• Multiple networking interfaces such as mesh, Wi-Fi, cellular, etc.

• Metrology interfaces to provide voltage, current, etc.

• Actuators such as relays and contactors

• Sensors including temperature, humidity, location, vibration and more

• Hardware watchdogs

• Generic hardware interfaces such as GPIO, ADC, SPI, etc.

Platform providers offering a GEISA EE MUST provide a toolchain which allows application developers to build applications written for the GEISA EE. [2]

11.1. Metrology

GEISA specifically addresses edge computing enviroments used by electric utilities. It is assumed there is a source of metrological data available on GEISA devices. The GEISA API provides a mechanism for GEISA applications to obtain details regarding the metrological capabilities of the device (see Platform Discovery)

Note

The GEISA API is not expected to provide metrological information when used on a non-metrological device; however, some platforms without local metrology MAY support providing remote metrological data through their local GEISA API

Metrological hardware, at a minimum, should be able to provide: [3]

• Instantaneous RMS Voltage Reading

• Instantaneous RMS Current Reading

• Frequency

When coupled with a billing register, metrological hardware may also be able to provide derived quantities such as demand values, cummulative values, and interval values.

Metrological hardware may also be able to provide waveform data. See Waveform Data for additional details.

When waveform data is provided, at a mininum, it SHALL provide:

• 128 samples per cycle (7.68 kHz at 60 Hz or 6.4 kHz at 50 Hz AC frequencies)

• 16 bits per sample

Platforms may provide higher sampling rates (e.g. 128, 256, 512, 16,384 samples per cycle or more) and greater sampling resolution (e.g. 32 bits per sample).

Depending on the device, waveform data may be provided for voltage, current, or both. Waveform data may be split-phase, phase-to-phase, or phase-to-neutral. The GEISA API allows applications to obtain details about the waveform data available on the platform so that they can correctly interpret the information the platform exposes through the API.

11.2. Sensors

A GEISA platform MAY optionally provide access to one or more sensors. Sensors are exposed through the GEISA API .

Examples of sensors that may be provided include:

• Temperature Sensor

• Humidity Sensor

• Switch Sensor

• GNSS Location

• Vibration / accelerometer

11.3. Actuators

A GEISA platform MAY optionally provide one or more actuators. Actuators are exposed through the GEISA API .

Examples of actuators that may be provided include:

• Service disconnect switch

• DER disconnect switch

• Demand response relay

[1]

Future versions of the GEISA specification may require binary compatibility, though it is likely this will only be done in conjunction with a GEISA community reference implementation.

[2]

GEISA LEE specifically assumes a GNU/Linux environment (see Operating System), such that it is likely that the tool chain in use is open-source. If a vendor is using a commercial tool chain, there is no requirement that the platform vendor provide a license; however, they MUST provide information regarding where third parties can purchase the necessary tool chain and the version of the tool chain in use, and they must provide any supporting files required to allow the tool chain to be used to compile applications for their platform.

[3]

Note: inductively powered devices, such a remote fault indicators, may lack a ground reference and thus may be unable to provide voltage data. Similarly, some devices may lack a current sensor and may thus be limited to voltage only. Electric meters are expected to be able to provide both.