Modbus and Meters


kshitiz

Recommended Posts

Hi,

I am a computer engineer and I have been assigned a task to read data from every type of meter like water, gas, electricity meter and store it in a database using java.

Now, I just want to know that whether modbus protocol used by all water meters or electricity meters is same or not? Or different water meters would be using different modbus protocol.

Similarly, modbus protocol used by water and any other meters like gas meters would be same or not ?

Please help me to give me a direction.

Thank you

Link to comment
Share on other sites

Different devices use different forms of Modbus (RTU/TCP/ASCII), though typically serial based devices use RTU and Ethernet based devices use TCP. That said, two different devices using the same version (say RTU), will almost certainly have completely different register mapping, and as such you can't write a universal driver.

Link to comment
Share on other sites

You can kind of think of it like telephone extensions. The Modbus ID will get you to the building, but if you want to reach accounting, it might be at extension 241 for Microsoft and 3829 for Dell, etc. Each device manufacturer will use different extensions to read their values. In addition to the register addresses (which correspond to the extensions) you have to know how they formatted their data, what data type. Modbus is pretty simple and pretty universal, but its not plug and play. In general you MUST have documentation for the device to get anywhere, and as far as I know, there is no standard for any particular sensor type, unless from a single manufacturer.

Link to comment
Share on other sites

  • 4 months later...
  • 3 months later...

Most smart meters have a Zigbee (wireless) technology component to them. They generally use the Zigbee Smart Energy implementation of Zigbee, you will need a compatible Zigbee radio implementation in order to connect to a Zigbee enabled Smart Meter. There are Zigbee "Smart Energy" gateways you can buy to gather the meter informaiton (if the utility lets you), depending what degree of secutity the meter has on it (good chance there is none).

Once you can access the meter data via Zigbee, you will need to implement a gateway function for converting the data to a useable form, either logged to a database or writing your own Modbus output. Digi has a gateway product that uses Python with Modbus, but you have to write (in Python) your Modbus maping (create your own registers). I have not tested this, I don't have a Zigbee Smart Energy gateway. I do have a Modbus Pro gateway that I have working with Zigbee sensors (e.g. light, temp, humidity), but I have not tried to map the sensor values to Modbus registries with Python. Digi lacks significant documentation in this area, they also lack "of the shelf" Zigbee Pro compatible sensors.

Link to comment
Share on other sites

  • 3 weeks later...

Archived

This topic is now archived and is closed to further replies.