Morningstar Suresine 300 "modbus"

RandomJoe

Does anyone know if the "modbus" mode on the Suresine 300 is true modbus? Or just the modbus protocol over another wire spec? The manual and Morningstar's modbus specifications doc make reference to "Meterbus" when talking about the PC adapter for modbus so I wondered...

I did find a bit of related discussion in a thread from last March, SG said here that there's an issue with isolation - so one side of the comm link is actually tied to ground? Ouch... Think I'd definitely want to isolate that...

I have an automation controller I'm starting to wire everything into, and just noticed the modbus listed on the inverter - would be pretty cool if I could just talk directly to it for data collection! Not so much looking to control it remotely, just be able to read status info. I already have a TED-style meter system that goes in the main breaker panel to monitor grid power, that will use modbus as well.

Thanks!
Joe

GreenerPower

Re: Morningstar Suresine 300 "modbus"

With the hub SG mentioned here, hopefully you can do want you want.

SG wrote:

MorningStar has a hub that can link 5 units together, then standard 4 conductor RJ11 cords between the Chargers and the Hub. The hub is for electrical isolation.

http://www.morningstarcorp.com/en/meterhub

GP

RandomJoe

Re: Morningstar Suresine 300 "modbus"

Forgot about that thread. But looking at the hub, Morningstar doesn't list the Suresine as one of the compatible devices. It also says that's to connect multiple devices to one meter, I believe the meter may use a different protocol. At least, there's a switch on the Suresine to select either Meterbus (for use with a remote meter) or Modbus (for use with a PC).

I shouldn't need a hub, if it does true modbus. I should be able to daisy-chain the various devices on a single comm link and set a different address for each. Unfortunately, in my work I have run across an awful lot of devices that either didn't implement the spec properly (for whatever spec, I get to try to work with many!) or went way off the reservation and did something completely incompatible but they used (some part of) the protocol so they stick the label on anyway! (No idea if Morningstar did that, that's what I'm trying to find out!)

The isolation issue is something I usually don't have to consider. The links I most commonly use are inherently isolated, the few I use that aren't the devices don't share power sources. Something I wouldn't have thought of if I hadn't seen SG's post.

westyd1982

Re: Morningstar Suresine 300 "modbus"

I have a SureSine-300 and a SunSaver MPPT. I used a standard telephone line 1-2 splitter plugged into my MSC and have had no trouble talking to both devices using the MODBUS interface. I was able to build a cool web-based system monitor running on my DC powered Linksys NSLU2 running Debian Linux. I've had it running for a few days, and so far it is working just great.

RandomJoe

Re: Morningstar Suresine 300 "modbus"

I had forgotten all about this, you gave something to play with tonight!

But so far no joy. I have the inverter connected to my automation panel, but can't get anything from it yet. At least, it fails the "ping test" to determine comm status. (I'm not any sort of Modbus expert, this is the first time I've tried to use it! Maybe someone else understands this?) I haven't created any points yet to see if they would work anyway. There is a setting for "ping address" that was defaulted to 0x0, not sure if I need to change that or what... (Best I can understand, it ought to be set to the address of one of the readable points in the device.)

One potential issue I have is, which pin of the RJ11 jack is + and which is -? I can't find anything that says, but have tried it both ways without success. (I'm assuming it uses the two center pins too..)

Does anyone know - is the Suresine actually RS-485? Somewhere in my miles of searching tonight I saw a reference to Modbus over RS-422, so thought perhaps that's a possibility... (The automation panel has an RS-485 connection, I was trying to connect directly.)

If it is RS-485, then I'm sure it's just a matter of finding the right settings. I have about a dozen different things I can set in addition to basic serial port settings, and Modbus is turning out to be quite confusing to me...!

Otherwise, I do have an RS-232 port on the panel as well. Perhaps I'll just get the Morningstar adapter if all else fails and use it... (Probably have to anyway, my other Modbus device - TED-style monitor - wants a different stop bit setting...)

Hope that rambling made sense. I'm tired and not thinking too clearly anymore tonight! :roll:

westyd1982

Re: Morningstar Suresine 300 "modbus"

RandomJoe -

I have had really good success communicating with the SureSine. I don't know anything about how Morningstar has wired the RJ-11 port. I use the MSC adaptor and it works well. The MODBUS connection is RTU serial , not TCP, so I don't think ping would work.

I communicate with my SureSine and my SunSaver MPPT from a low-power (<5 watts) LINUX box. I posted some example software at http://westyd1982.wordpress.com/.

RandomJoe

Re: Morningstar Suresine 300 "modbus"

This isn't a TCP/IP ping. It's just (from what I understand) that the controller "pings" the address specified (0x0 is usually the first point available to be read in the controller) to see if it gets a response. As opposed to doing a full read, where it would need to know more about what it is to get back. All it's supposed to be for is to verify communication with the device.

Again, that's just what I understand from reading the (rather limited) docs. I've never used Modbus before, didn't realize it was so much less straightforward than the other protocols I've used (various forms of Bacnet and LON, primarily).

I may try setting up some points and see if they read. If so, I don't really care what the ping test does!

RandomJoe

Re: Morningstar Suresine 300 "modbus"

I finally thought to look at the docs for the MSC, and it was more descriptive of the various comm links used by Morningstar than the others. While it still doesn't say what wire protocol is used on the Suresine and other devices (just calls it the "RJ11" protocol!) it does make clear that they are not using RS-485 on these devices.

So, looks like I'll need the MSC after all. Ordered one yesterday, guess I have a project for next weekend once it arrives.