Intelligent electronic device and method thereof
Provided are a method and apparatus for communication between a CPU and a Digital Signal Processor (DSP) in an Intelligent Electronic Device (IED). Specifically, the IED includes at least one analog-to-digital converter coupled to at least one sensor and configured for converting an analog signal output from the at least one sensor to digital data; a DSP coupled to the at least one analog-to-digital converter, and configured to perform digital signal processing on the signal from the at least one analog-to-digital converter; a CPU coupled to the DSP via a hardware path; wherein the DSP and the CPU are configured to communicate using a transmission protocol including a data header and a data payload based on the hardware path; wherein the data header includes a field of command identification indicating a specific communication purpose and a field of command type indicating the communication direction and frequency.
1. An Intelligent Electronic Device (IED) comprising:
at least one sensor configured for sensing at least one electrical parameter of electrical power distributed from an electrical distribution system to a load;
at least one analog-to-digital converter coupled to the at least one sensor and configured for converting an analog signal output from the at least one sensor to digital data;
a Digital Signal Processor (DSP) coupled to the at least one analog-to-digital converter, and configured to perform digital signal processing on the the digital data from the at least one analog-to-digital converter;
a CPU coupled to the DSP via a hardware path; and
wherein the DSP and the CPU are configured to communicate using a transmission protocol comprising a packet structure, the packet structure including:
a header comprising a wakeup word, a packet header, a packet type, a packet length, and a packet counter;
a data header including a field of command identification indicating a specific communication purpose and a field of command type indicating the communication direction and frequency;
a data payload; and
a footer comprising a checksum, an ending wakeup word, and a closure word;
wherein the command type comprises:
a request command packet sent from the CPU to the DSP;
a periodic command packet sent from the DSP to the CPU; and
an event-triggered command packet sent from the DSP to the CPU.
2. The IED of claim 1 , wherein the request command sent from the CPU to the DSP comprises at least one of:
an on-demand request command packet sent from the CPU to the DSP configured to be executed multiple times after the IED starts; and
a one-time request command packet sent from the CPU to the DSP configured to be executed only once after the IED starts.
3. The IED of claim 2 , wherein the one-time request command packet comprises a DSP_START command packet having a command type value of 0x02 and a command ID value of 0x04, wherein the DSP_START command packet is configured to trigger the DSP to start processing the digital data from the analog-to-digital converter.
4. The IED of claim 2 , wherein the on-demand request command packet comprises a DSP_CONFIG command packet having a command type value of 0x01 and a command ID value of 0x06, wherein the DSP_CONFIG command packet includes configuration parameters comprising primary nominal voltage, wire type, and harmonic configuration.
5. The IED of claim 1 , wherein the periodic command packet comprises a frequency measurement command packet having a command type value of 0x03 and a command ID value of 0x0F, configured to be sent from the DSP to the CPU every 10 seconds with frequency measurement data; and the event-triggered command packet comprises a transient voltage command packet having a command type value of 0x04 and a command ID value of 0x24, configured to be sent from the DSP to the CPU when a transient voltage event is detected.