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Forum Index : Electronics : Energy Meter Wiring
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Madness Guru  Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I have one of these Eastron SDM 220 Modbus meters. After a bit of fiddling around, I finally got it communicating via RS485 with my Zevercom device for my Grid Tie Inverters. However, the Zevercom is telling me that my power consumption is exactly the same as power produced by the GTIs. Has anybody else had experience with these, I can't fiddle around too much with it ATM as it is wired into the house power now and I have to shut down everything to work on it. This is how I wired the meter, I am treating the off-grid inverter as if it were the grid. So exported power is what is going to the Battery via the off grid inverter.  This all that the GTI manufacturer shows  There are only 10 types of people in the world: those who understand binary, and those who don't. |
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Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
Mad, out of curiosity I tried to download the manual of this meter from the link above. My virus program shut down this process as it thinks that PDF file is infected with a virus. So I'm not going to look at that manual and since I'm unfamiliar with these meters I dunno... But, if your Zevercom tells you all your power is coming from the GTI I would think your batteries are full and your GTI can handle the power the house requires for the moment. Try the same again when the batteries are low. Klaus |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
I get the same virus error from one source of the manual but not from others. The meter is reporting zero net export which is not correct, it is supposed to give power produced by the GTI's, power consumed and net power exported. All get is generation and consumption being equal all day with nil export. My battery is not full ATM it got to 97% today due to cloudy weather. I think I should try connecting the GTI to the same side of the meter as the Off-Grid Inverter. Here is the graph, net is shown flatlining across the bottom, Generation and Consumption are the same value all day.  There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Tinker Guru Joined: 07/11/2007 Location: AustraliaPosts: 1904 |
There is a link shown on that meter sketch, if its there it should not matter which side your OGI is connected. I'm not game to look up the manual  Klaus |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
I've got mine wired similarly, but one on the input & the other the output of my Hybrid. One curious thing though is I am seeing power fed back into the grid on occasions even though that option is disabled. Re the manuals. I've had no virus warnings & the originals are located here... http://www.eastrongroup.com/ Or more specifically here. http://www.eastrongroup.com/productsview/49.html Phil. Edit, exactly where your original link pointed. Read before posting Phil..... |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
That link has a Hall Effect Sensor on it, it is not just a link. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Hi Phil, Can you be a bit more specific please, are you say there is 2 meters? There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
First meter has Grid to Pin 1, Pin 2 to input of my inverter. Second meter has Inverter output to Pin 1, Pin 2 to load. Both RS485 in parallel & talking but that solution is still work in progress. It's the first meter that is showing some Export even though that is disabled. Not much, (wait while I walk...)... About .07kWh per day. I've caught in in the act of exporting by chance, usually when Input & Output loads are near equal. And at that point in time it shows power as -ve watts, maybe 10-50 & power factor is really low, like 0.2. Phil. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Not quite sure which readings you mean. Consumption as read from the Eastron? Edit Clarifying my previous post. I have two meters side by side. One for inverter input, the other output. |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
The consumption/export should be coming from the Eastron Meter and power generated from the GTI's. At that is what I was expecting, but when I get the chance I will switch the GTI's output to pin one on the Eastron Meter and see if it makes more sense then. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
I am away for quite a few days and am unable to get to my computer to look stuff up. there is a few things. I dont think that protocol document is the latest, I am pretty sure csongor varga has a youtube video for the sbm120 and he has a link to a later version file in the video description for that device. it might be the same but it might pay to have a look at a later version and see if something has changed. His video might help or it might confuse the hell out of you, I saw it about 7 months ago. modbus can be a bit quirky to work with, it might be polling the wrong register address to get import + export or total energy or whatever it is called. total active energy??? nup, my memory is shot, I will have to look it up. the values on these meters are a float value it is using 2 consecutive register addresses to calculate things, to get it to read it might need to be told to look at them as a pair, a setting might need to be changed from a 1 to a 2. If you are not in a hurry we can have a look to see if it is possible to adjust some settings when I get back home. I'm confused, no wait... maybe I'm not... |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Been playing with a bit of code for this the last week or so. There's a bit of it over in the Micromite forum. So far have IEEE754 decoded & CRC dealt with. Just need to build the request frames now & pull apart the response. One thing I don't have clear in my head is the two addresses shown in the table. I'm getting data from the one's on the right, like Active Power, 00 0C not sure of the relevance of 30013 & presume it's the register I get anyway. Modbus is totally new to me....  Phil. |
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| yahoo2 Guru Joined: 05/04/2011 Location: AustraliaPosts: 1166 |
Thanks phil that table helps. what you are looking at in the left and right columns is the same thing, the address register on the left is decimal starting at 1 and the right column is a hex start address which starts at 0. some machines want you to enter the hex value expressed as a decimal, to get address 0013 you would enter 12 because 12 is the 13th number starting at zero  the last four digits of active power 0013 and hex 00 0C (12) are the same address. so the complete list of allocated addresses for a 3 phase meter active power would be phase 1 0013 (00 0C) 0014 (00 0D) phase 2 0015 (00 0E) 0016 (00 0F) phase 3 0017 (00 10) 0018 (00 11) if you look at the table the next address is 0019 for apparent power so this allocation of numbers repeats itself again. when you poll the meter for data you have a couple of options, you can request a range and grab the lot as a big chunk and let the master sort out the bits it needs or you can poll individual addresses. there is usually an option to use the first address OR select the pair together and calculate a float value. That table has not got total energy listed, there should be some allocated addresses between 0330 and 0350 from what I can remember. I'm confused, no wait... maybe I'm not... |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Yeah, Sorry, It continued on the next page...  |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
The video Yahoo referred to can be seen here it goes into quite a bit of detail about getting the data from the meter. I think my problem is there is no data coming out of the meter or it is not able to communicate with the Zevercom device. I changed the wiring around and it has no effect on the charts. Also I emailed Zeverrsolar about what settings are required but no response as yet. I have ordered some RS485 to TTL converters which are very cheap on Aliexpress so I can use an Arduino to talk to it. May end up using the Arduino to regulate the GTI's via RS485 instead of the PCB and MOSFETs in series with the panels. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
I got the same modules initially, but ordered these others as well. They seem to work fine when connected to a USB-TTL CP2102 module. Can talk to the meters with some Modbus software I found. These, https://www.aliexpress.com/item/TTL-turn-RS485-module-485-to-serial-UART-level-mutual-conversion-hardware-automatic-flow -control/32709226383.html?spm=a2g0s.9042311.0.0.0pGBWV They might be easier to live with as they handle the flow control themselves.  |
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| Madness Guru Joined: 08/10/2011 Location: AustraliaPosts: 2498 |
Phil have you had to add the 120-ohm resistors to terminate the RS485? Thanks for that link, I have ordered some of those modules also. There are only 10 types of people in the world: those who understand binary, and those who don't. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Yes have a 120 on the first meter, then it parallels with the second one. The module has its own terminator, R9, just above the A & B connections. Waiting on a couple more plus an SDM120CT (Current Transformer version). When they arrive I'll add one to the incoming Grid supply in the main meter box & add it as well. Not sure if I'll cable it back to the solar cabinet, 15m away or just give it it's own Micromite. 15m of cable & installation Vs 28 Pin Micromite or E28......... $8-$10 ESP-01 Wifi Module.............. $2.50 HC-11 433Mhz Module............. $4.00 2nd RS485-TTL Module............ $2.00 Probably easier that running the wire properly. Will temporarily string it up initially... For the first couple of years. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Not having a lot of luck finding out how to Poll multiple Input Registers in a single request. Is that always possible? I see examples of reading multiples for other types of registers & multiple writes, but missing on seeing reading multiple for Input Registers. At the moment I'm polling them individually. Phil. |
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| Phil23 Guru Joined: 27/03/2016 Location: AustraliaPosts: 1664 |
Pretty much got it sorted now. Reading the first block of registers all in one hit. [Code] $ð 01:04:00:00:00:24:F0:11: Volts : 241.17 Amps : 6.74 Watts : 1371.38 VA : 1625.47 VAr : -872.62 P/Factor : 0.84 01 04 48 43 71 01 9E 00 00 00 00 00 00 00 00 40 DC 65 47 00 00 00 00 00 00 00 00 44 B0 90 11 00 00 00 00 00 00 00 00 44 CF 7C BC 00 00 00 00 00 00 00 00 C4 59 F5 8C 00 00 00 00 00 00 00 00 3F 59 D7 EC 00 00 00 00 00 00 00 00 7D 46 Length= 154 >[/code] Have it also displaying on a 2.8" LCD screen. Just needs some decent formatting now & overall a bit of polishing. Still TOTALLY work in progress, but here's a bit of an idea of how it might fit on the display.  I can fit 10 lines by 18 Chrs with that font, so should be able to list output from 2 meters side by side. Bottom left is an ESP8266 that connects to the console. Nice thing about that is I can access it from any PC as well as mobile devices via a VT100 terminal. Just need to tidy up all the code now & present the data better in the Console & LCD interfaces. Phil. Edit the VT output at the top show the request string I'm sending & the 154 byte response coming back. |
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