Control.com - Nerds in Control

I am with the Power Generation Division of the U.S. Army's Communications-Electronics Research, Development and Engineering Center, Aberdeen Proving Ground, MD.

We are interested in monitorinng and controlling engine driven portable generators and their loads via MODBUS. We envision several generators and loads colocated in a small area all connected via MODBUS. We further envision connecting this local network to a larger network via Ethernet TCP/IP. We are looking essentially for an evaluation kit to get started with. This would consist of an Ethernet TCP/IP equipped master and several slave units, the latter haveing relay closures for control purposes and A/D converters to monitor device functions. We have been unable to find a suitable package that would get us started.

Sounds almost like you want to make your own box.

However, there are LOTS of 'Modbus Load Curtailment/Demand Control' devices out there - many can tell you the current/load as well as will have large power relays to power on/off the load.

One partner we've worked with is http://www.measurlogic.com/, but most firms which make a "Modbus speaking power sub-meter" will also have the ability to manage a remote load. So SquareD, Schneider-Electric, etc will all sell.

If I understand your problem correctly, it is easily solved by off the shelf components. I know it isn't as sexy as making your own, but it's much less expensive. See links below for some (but definitely not all) solutions.

http://www.woodward.com/easygen3000series.aspx

http://www.governors-america.com/genset_controllers.html

http://www.deepseaplc.com/products/dse-genset/

http://www.basler.com/html/rscdev.htm

I appreciate your response and looked at some of your references. They seem to partially solve the problem, but appear to be too sophisticated for some of our applications. We would like a simple, commercially available interface box with maybe a relay closure or two, and some A/D for monitoring.

Fair enough. Then sounds like you want a PLC or something of that like.

For another example see this link. Obviously other manufactuers may have similar products. Look at the DirectLogic 05 and the ethernet/modbus module: http://www.automationdirect.com/adc/Shopping/Catalog/Programmable_Cont rollers

They have the click series too which are super inexpensive, but I don't think they will do analog I/O as of yet.

You may also be interested in IPERC. http://www.iperc.us/

Hello Thomas-

Please Google "Woodward TQG", or check out: http://www.youtube.com/watch?v=Do5jUAP5iCU

Any of the above mentioned controler models with Modbus protocol should be capable of starting/stopping and monitoring gensets. On ECU equipped gensets engine parameters can be read over CAN J1939 and mapped to Modbus. On older sets you can bring in some analog values and convert to Modbus for remote monitoring of oil pressure, water temp, etc. Once you start the gens you still need a controller to synch, parallel and load share with other units.

As stated in the previous post there are affordable COTS solutions available, some that include features for automatically starting and stopping generators in a system based on changing load demand (LDSS). LDSS is done on a peer-to-peer network- it does not require a supervisory "microgrid" controller. There are some things a supervisory microgrid controller can do that a genset controller alone can't, like anticipate load changes and shed load if needed, but having a layered control archetecture with LDSS available in the genset controllers will help you build a robust control system for tactical applications. I'd love to discuss this more with you.