Wireline Communications IP

Does your system have multiple converters?  Having trouble communicating between converters with the latency you require?   Having issues with common-mode noise disrupting your communications?  Reliability not good enough?  ELMG has the product for you.

ELMG wireline communications IP is a FPGA IP block which sends a self-clocking serial packet data stream down differential wire pairs at rates of up to 100Mbps.  With a customizable message packet both latency critical data and non-critical data can be sent over the stream from one unit to many controllers in a point to multipoint arrangement.  ELMG’s solution also provides synchronization through PLLs to ensure that all converters are all in-sync.

How Does It Work

ELMG’s wireline communications works by first encoding your message data into 8b10 codes.  Use of these codes allows special codes for message framing, synchronization and clocking.  Using a finite state machine, the message packet is formed.  Following the header the latency-critical encoded data is sent followed by its CRC.  This allows the latency-critical data to be used by the receiver immediately after it is checked for errors.  Synchronization codes follow and then the message ends with the latency-non-critical data and it’s CRC.   This system uses error-detection but can be customized to use error-correction at the expense of latency.

Benefits of the IP

One of the key benefits of this IP is the ability to send data long distances using noise resistant differential wire pairs.  This can be very important in large power converter systems which fill the environment with disruptive common-mode noise during switching.  It also allows you to reduce costs by reducing the number of pairs to one-per-direction as the clock and data are multiplexed.  Further benefits allow customization of the message packet to allow you to help determine the tradeoffs between throughput and latency that are fixed in other systems.

Additional Services

As well as assisting you in customizing your IP, ELMG can help with your choices of physical layer and partitioning your data into latency-critical and latency non-critical components.  Reducing the amount of latency-critical data reduces the latency and/or the cost of your physical layer solution by reducing throughput.  ELMG can also assist in analysis of your control loop to determine the maximum latency that is tolerable before your control loop is too adversely affected.

Field Buses

Need an industry standard communications solution?  Need to talk to PLCs or industrial PCs?  A field bus is the solution for you.  ELMG provides two field bus solutions: Powerlink and Ethercat.

Why Powerlink and Ethercat?

The first point of commonality between these two buses is that they are both industrial Ethernet solutions.  In these modern times, the Ethernet based solutions have replaced the serial bus (such as RS485) based solutions such as Profibus and Modbus.   The second point they have in common is that they are low latency compared with others such as Profinet and Ethernet/IP.  This is because they have based their solution not on TCP/IP but on custom transport and data link layers.  This allows them to be burdened into the long latencies of TCP especially.  However, don’t worry if part of your system uses SERCOS or Profinet, or even a serial field bus, there are third-party products that can convert between two different field buses to allow your diverse system to function smoothly.

Powerlink and Ethercat are both good solutions and each has its own strengths and weaknesses.  The field bus that is right for you will be application dependent and ELMG can help determine which would suit your application better.

Additional Services

As well as providing a full field bus solution, ELMG can help determine what data needs to be sent across the bus and how minimize latency.  ELMG can also assist in analysis of your control loop to determine the maximum latency that is tolerable before your control loop is too adversely affected.