One Classic 250 MNGP's mirrors the other Classic 250

[Trukinbear]

Hi, I've got two MidNite Classic 250 charge controllers networked together with my SMA Sunny Island SI6048 via a MidNite MODBUS/Canbus SMA communications adaptor.

I'm having a weird issue = both Classic 250's MNGP's display the info for the primary Classic 250.

I can 'fix' it but that causes other problems. If I leave the MODBUS address on the 2nd unit set to the default of 10 (like the primary) then it displays it's own info but my Sunny Island can't see it. When I change the MODBUS address on the 2nd unit to 11 (like it is supposed to be) then it shows the display of the primary Classic 250, not it's own - BUT the Sunny Island can see it just fine (as can the local app either way).

What am I missing? This didn't start happening (or I didn't notice it) until my primary 250 went down - now back from warranty service (thanks guys) it still does this.

Can anybody help?

[boB]

Oh my.  That is weird (I think)

Have you tried hooking up the MNGP to the "other"  Classic instead ?

Or maybe trying to swap the addresses, 10 and 11 to  11 and 10  for the two Classics ?

I would try moving the MNGP first.

[Trukinbear]

What do you mean, swap the covers between the two units? I must be mistaken but isnt that where the memory resides - will I then have to reprogram BOTH of them AND reroute the network cables - or am I overthinking this?

I've tried the other way around with the MODBUS addresses and unless the last Classic in the chain (that is attached to the MODBUS/Canbus com deal) is set to 10 then the Sunny Island can't see either Classic on the network. As it is the MODBUS/Canbus is MODBUS 9, the primary Classic attached to it MODBUS 10, and the other Classic is supposed to be 11.

[Trukinbear]

The Sunny Island is reading both of them perfectly, and so does the local app - it's just both of them have the display of the primary.

The Classic 250 on the Left should be named West and have a totally different set of numbers displayed.

South array has produced squat today thanks to our blanket of smoke overhead.

I can display different screens at the same time, but they are both of the Right Classic 250 'south'

West has the temp sensor and Whizbang Jr which both look fine on the local app but don't show up on these MNGP displays.

[boB]

Ya know, I can't remember but it MAY be that this is normal ?   Or did you say that this used to work as expected ?

The MNGP display (cover) is not where the memory resides.  That resides inside the Classic itself.

The MNGP is actually just a window into the Classic's settings but it can auto-program the Classic with the 2-finger vulcan mind meld usually done when setting up a new system.   A "terminal" is what the MNGP is.

Have you asked anyone in our support group about this ?   This forum is a good place to start though of course and the support folks will eventually see this (hopefully)

If not, I can prod them  😁

boB

[Resthome]

Are these Classic set up in follow me mode? 

Something isn’t configured or wired correctly as they both show the same Serial Number.

Can you provide a drawing of how the Classic cables are connected inside the top cover?

[Trukinbear]

If I change the MODBUS address back to 10 then the unit displays properly but the Sunny Island can't see it. Not follow me - SMA - these are controlled by the SMA SI6048 via the MODBUS/Canbus adaptor.

Left most unit 'West' MODBUS address 11 is connected to the Right most unit 'South' MODBUS address 10 by a phone line that goes from 'slave out' on 'West' to 'master in' on 'South.' A CAT-5 cable then goes from the 'slave out' on 'south' (MODBUS 10) to the RJ-11 connector  'MODBUS IN' on the MidNite Solar MODBUS/Canbus Comm Adaptor for SMA. Another cable goes from the Canbus port on the Comm Adaptor to the RJ-45 marked 'COM SYNC' on the SMA Sunny Island SI6048 and a 'bus terminator' in the RJ-45 marked 'COM SYNC OUT' on the SI6048. Both Classic 250's are set to 'SMA MODE.'

[boB]

Are these Classic set up in follow me mode? 

Something isn’t configured or wired correctly as they both show the same Serial Number.

Can you provide a drawing of how the Classic cables are connected inside the top cover?

SMA mode works a bit differently than the normal RS-232 MODBUS networking mode for this setup.

CANBUS from the SMA Sunny Island goes into our box that translates SMA speak to Classic speak.

We do a bit extra than what normal RS-232 MODBUS does.  The Classic has the two RS-232 ports (not including Ethernet and the MNGP port) that normally will pass packets through if the modbus address (10, 11, 12 etc) does not match.  This is normally bidirectional too. 

In  one mode, the packets flow only one direction and that is why you have to have a loop for Follow-Me mode.  Also, in F-Me mode, the address is given as not 10 or 11 etc but as address 255.  Another no-no for the modbus spec but we use it anyway.  When a Classic see an address of 255 come in, it takes it as its own, even if its address is programmed to be 10 or 11 etc. That packet is not passed through also.  Each Classic's neighbor in Follow-Me mode is addressed as 255.

In the regular Classic mode, the packets can go either way and pass through but I think that Follow-Me itself just makes it go one direction so the MNGP should still work to address a neighboring unit.

In SMA mode, it is different and I am trying to remember what that difference is.  I MAY be that the packets only go in one direction and that an MNGP can not address a unit down-stream.  Or the unit down-stream may see the MNGPs packet but that MNGP can not receive the packet from the downstream Classic.

I have to look to remember how that works.  I will try to look for that this weekend.

[Trukinbear]

This is the manual (flyer) that tech support told me (quite rudely) on the phone last year had everything I needed to know.

[Wizbandit]

Remove all COMMBOX routing cables before trying the address the Classics.  You are re-addressing #1 to address 11 across the cables.

[Trukinbear]

Remove all COMMBOX routing cables before trying the address the Classics.  You are re-addressing #1 to address 11 across the cables.

I did readdress them before connecting back to the MODBUS/Canbus combox, and they appear in the local app to be addressed correctly, but I'll try that again.

[Trukinbear]

Remove all COMMBOX routing cables before trying the address the Classics.  You are re-addressing #1 to address 11 across the cables.

Ok, I did it that way and now the 'West' unit (MODBUS 11) never has it's own display - it displays a mirror of 'South' (MODBUS 10) MNGP and if you power down 'South' the display on 'West' changes to zeros and 'GOT COMM?' You can go thru the menus but can't save anything. I changed out the MNGP cable and same thing. Also displays 'GOT COMM?' if the master/slave cable isn't hooked up. Numbers show up OK on local app, and the SI can see both of them on the SMA network so this just may be an annoyance I can live with... but it wasn't like this for almost a year so I fear it's a harbinger of doom.

Oddly if 'West' is set to (MODBUS 10) it has it's own display but doesn't show up on the SMA.

GOT COMM?

I guess I could try swapping positions of the Classics out and see what happens?

[boB]

Have you tried changing the cables ?   

I think that's a last ditch effort question though since I'm not sure why it would still work like it is working.

It   IS   full-duplex RS-232 though so maybe ?

I only mention this because you said it worked as expected for a year so I am wondering what changed ?

[Trukinbear]

I only mention this because you said it worked as expected for a year so I am wondering what changed ?

The primary unit 'South' died 3 or 4 weeks ago and this was one of the weird things I noticed when it did. The unit 'South' was repaired under warranty and just came back a few days ago. When it died was when I first noticed this.

[boB]

I only mention this because you said it worked as expected for a year so I am wondering what changed ?

The primary unit 'South' died 3 or 4 weeks ago and this was one of the weird things I noticed when it did. The unit 'South' was repaired under warranty and just came back a few days ago. When it died was when I first noticed this.

AHA !  OK.  Then you will probably have to take one MNGP and plug it into the repaired Classic.  THEN change its address to 11 or 12 or whatever it needs to be set to.

You cannot change a Classic's modbus address over the network if I remember correctly.    This would be because the MNGP that is plugged into the Classic will be sent using modbus address 255.  Sending through address 255 tells the Classic to stop there and not forward over the network cable.

So, if the MNGP is plugged into a Classic that is set for address 10 and the MNGP is talking on 10, they will take together fine OR at address 10 or 255.  If that MNGP tries to change its Classic  and the MNGP changes to address 11, the the Classic it is trying to change will not see the command because it is still at address 10.  But if the MNGP talks over address 255, then the Classic it is connected to will see the command to change to address 11 but using address 255.  Address 255 is a catch-all address for a Classic for this and other purposes.

You should not have to change the address in the MNGP to 255 though.  The function of changing the modbus address automatically should do that.  But the MNGP or any MNGP needs to temporarily at least be plugged into the classic needing the address change.   Then the MNGP can be moved back to the original Classic and its MNGP address changed back to 10 or whatever it was at before.