Hiking DDS238-2 ZN/S energy meter

DDS238-2 ZN-S Modbus.md

Hiking DDS238-2 ZN/S energy meter

Document included in the project https://github.com/fawno/Modbus

https://github.com/fawno/Modbus/blob/master/DDS238-2%20ZN-S%20Modbus.md

Modbus holding registers:

Register(s)	Meaning	Scale Unit	Data format	R/W
0000h-0001h	total energy	1/100 kWh	unsigned dword	R¹
0002h-0003h	reserved		unsigned dword
0004h-0005h	reserved		unsigned dword
0006h-0007h	reserved		unsigned dword
0008h-0009h	export energy	1/100 kWh	unsigned dword	R¹
000Ah-000Bh	import energy	1/100 kWh	unsigned dword	R¹
000Ch	voltage	1/10 V	unsigned word	R
000Dh	current	1/100 A	unsigned word	R
000Eh	active power	1 W	signed word	R
000Fh	reactive power	1 VAr	unsigned word	R
0010h	power factor	1/1000	unsigned word	R
0011h	frequency	1/100 Hz	unsigned word	R
0012h	reserved		unsigned word
0013h	reserved		unsigned word
0014h	reserved		unsigned word
0015h:high	station address	1-247	unsigned char	R/W
0015h:low	baud rate	1-4²	unsigned char	R/W
001Ah	relay³		unsigned word	R/W

Notes:

Note 1:

Total, export and import energy counters can erased writing 0 in total energy registers.

Note 2:

Value mapping, default 1.

Value	Baud rate
1	9600 Bd
2	4800 Bd
3	2400 Bd
4	1200 Bd

Note 3:

In DDS238-2 ZN/SR model the relay can be switched by 0x001A register.

Value	Relay
0	Off
1	On

Data formats

Data format	Lenght	Byte order
char	8 bits
word	16 bits	Big endian
dword	32 bits	Big endian

Writing registers

The meter does not understand the 'write sigle register' function code (06h), only the 'write multiple registers' function code (10h).

dds238-read.php

<?php
  function set_win_port_attr ($port_name = 'com1:', $port_attr = ['baud' => 9600, 'data' => 8, 'stop' => 1, 'parity' => 'n']) {
    $mode = 'mode ' . $port_name;
    foreach ($port_attr as $attr => $value) {
      $mode .= ' ' . $attr . '=' . $value;
    }

    exec($mode, $output, $return);

    return $return;
  }

  function crc16 ($data) {
    $crc = 0xFFFF;
    foreach (unpack('C*', $data) as $byte) {
      $crc ^= $byte;
      for ($j = 8; $j; $j--) {
        $crc = ($crc >> 1) ^ (($crc & 0x0001) * 0xA001);
      }
    }

    return pack('v1', $crc);
  }

  $modbus_message_format = [
    'address' => 'C1',
    'function' => 'C1',
    'start' => 'n1',
    'quantity' => 'n1',
    //'crc' => 'n1',
  ];

  $modbus_message_pack = implode($modbus_message_format);
  $modbus_message_unpack = null;
  foreach ($modbus_message_format as $name => $format) {
    $modbus_message_unpack .= $format . $name . '/';
  }

  $modbus_response_format = [
    'address' => 'C1',
    'function' => 'C1',
    'count' => 'C1',
    'total_energy' => 'N1',
    'reserved' => 'N3',
    'export_energy' => 'N1',
    'import_energy' => 'N1',
    'voltage' => 'n1',
    'current' => 'n1',
    'active_power' => 'n1',
    'reactive_power' => 'n1',
    'power_factor' => 'n1',
    'frecuency' => 'n1',
    //'year' => 'C1',
    //'month' => 'C1',
    //'day' => 'C1',
    //'hour' => 'C1',
    //'minute' => 'C1',
    //'second' => 'C1',
    //'comm_addr' => 'C1',
    //'comm_baud' => 'C1',
    //'trip_energy' => 'N1',
    //'trip_time' => 'N1',
    //'unknow' => 'n5',
    //'month2' => 'C1',
    //'day2' => 'C1',
    'crc' => 'n1',
  ];

  $modbus_response_pack = implode($modbus_response_format);
  $modbus_response_unpack = null;
  foreach ($modbus_response_format as $name => $format) {
    $modbus_response_unpack .= $format . $name . '/';
  }

  $port_name = 'COM3:';
  $port_attr = ['baud' => 9600, 'data' => 8, 'stop' => 1, 'parity' => 'n', 'xon' => 'off'];
  set_win_port_attr($port_name, $port_attr);

  $modbus = fopen($port_name, 'rb+');

  $message = [0x01, 0x03, 0, 18];
  $message = pack($modbus_message_pack, ...$message);
  $message .= crc16($message);

  fwrite($modbus, $message);

  $buffer = null;
  do {
    usleep($buffer ? 5000 : 100000);
    $buffer .= fread($modbus, 1);
  } while (!feof($modbus));

  if (crc16(substr($buffer, 0, -2)) != substr($buffer, -2)) {
    echo __LINE__, PHP_EOL;
    echo bin2hex($buffer), PHP_EOL;
    echo bin2hex(substr($buffer, 0, -2)), PHP_EOL;
    echo bin2hex(substr($buffer, -2)), PHP_EOL;
    die();
  }

  $response = unpack($modbus_response_unpack, $buffer);

  //print_r($response);

  $data_scale = [
    'total_energy' => 1/100,  // daWh / 100 => kWh
    'export_energy' => 1/100, // daWh / 100 => kWh
    'import_energy' => 1/100, // daWh / 100 => kWh
    'voltage' => 1/10,        // dV / 10 => V
    'current' => 1/100,       // cA / 100 => A
    'active_power' => 1,      // W
    'reactive_power' => 1,    // VA
    'power_factor' => 1/1000,
    'frecuency' => 1/100,     // cHz / 100 => Hz
    //'comm_addr' => 1,
    //'comm_baud' => 1,         // [1 => 9600, 2 => 4800, 3 => 2400, 4 => 1200]
    //'trip_energy' => 1/100,   // daWh / 100 => kWh
  ];

  $data = [];
  foreach ($data_scale as $key => $scale) {
    $data[$key] = isset($response[$key]) ? $response[$key] * $scale : null;
  }

  print_r($data);

  echo "\nok";
  fclose($modbus);

dds238-reset-energy-counters.php

<?php
  function set_win_port_attr ($port_name = 'com1:', $port_attr = ['baud' => 9600, 'data' => 8, 'stop' => 1, 'parity' => 'n']) {
    $mode = 'mode ' . $port_name;
    foreach ($port_attr as $attr => $value) {
      $mode .= ' ' . $attr . '=' . $value;
    }

    exec($mode, $output, $return);

    return $return;
  }

  function crc16 ($data) {
    $crc = 0xFFFF;
    foreach (unpack('C*', $data) as $byte) {
      $crc ^= $byte;
      for ($j = 8; $j; $j--) {
        $crc = ($crc >> 1) ^ (($crc & 0x0001) * 0xA001);
      }
    }

    return pack('v1', $crc);
  }

  $port_name = 'COM3:';
  $port_attr = ['baud' => 9600, 'data' => 8, 'stop' => 1, 'parity' => 'n', 'xon' => 'off'];
  set_win_port_attr($port_name, $port_attr);

  $modbus = fopen($port_name, 'rb+');

  //| 0000h-0001h | total energy    | 1/100 kWh  | unsigned dword | R/W |
  $message = [0x01, 0x10, 0x0000, 2, 4, 0];
  $message = pack('C1C1n1n1C1N1', ...$message);
  $message .= crc16($message);

  fwrite($modbus, $message);

  fclose($modbus);

Have you played with the wifi version of this? I'm keen to know if I can talk to it via wifi?

I have only tried the serial version of modbus. I do not know if in the wifi version (modbus over ip) the protocol is the same, although it sounds reasonable that it is so.

Thx, you help me with first picture of Modbus addresses to communicate this energy meter to my scada system.
Edit: I cannot change Modbus ID adress - I tried sw QmodMaster... unsuccessfully, some other idea for another SW ?

Thx, you help me with first picture of Modbus addresses to communicate this energy meter to my scada system.
Edit: I cannot change Modbus ID adress - I tried sw QmodMaster... unsuccessfully, some other idea for another SW ?

Try this to change slave ID https://www.domoticz.com/wiki/Python_-_Read-out_of_DDS238_kWh-meter_and_upload_to_Domoticz_and_to_PVOutput#More_than_1_kWh-meter_type_DDS238-1ZN_or_other_kWH-meters_in_the_configuration

Thx, but I have already managed to get the SW with which I have already changed the ID on both electricity meters 👍

FYI There is a variant DDS238-2 ZN/SR that can switch the output by writing at register 0x001A:

//Type DDS238-2 ZN/SR
//0x001A register = relay  
//0000 = off, 0001 = on
//id func reg  datanr len data crc   
//00 10   001A 0001   02  0000 A9FA = relay on
//00 10   001A 0001   02  0001 683A = relay off

echo "\nswitch off\n";
  $message = [0x00, 0x10, 0x001A, 0x0001, 0x02, 0];
  $message = pack('C1C1n1n1C1n1', ...$message);
  $message .= crc16($message);
  echo bin2hex($message);
  fwrite($modbus, $message);

sleep(3);

echo "\nswitch on\n";
  $message = [0x00, 0x10, 0x001A, 0x0001, 0x02, 1];
  $message = pack('C1C1n1n1C1n1', ...$message);
  $message .= crc16($message);
  echo bin2hex($message);
  fwrite($modbus, $message);

@analystcmyk

FYI There is a variant DDS238-2 ZN/SR that can switch the output by writing at register 0x001A:

Thanks for the information, updated table of records.

Hola,
Estoy buscando un programa para ejecutarlo en Arduino mega.
Dispongo de un módulo max485.
Mis conocimientos son bastante limitados.
Si me podéis hechar una mano os lo agradecería.
He probado algunos ejemplos sin éxito.

El meditor es de dds238-2 zn.
Gracias

@PepeLuis1959
En parte mi idea era realizar un dataloger con Arduino y o bien descargar datos mediante eth o bien que se suban los datos cada tanto a una web.
Por cosas de la vida tengo el proyecto aparcado y tal vez cuando lo retome lo haga mediante una Rasberry o similar ya que además de poder reutilizar el código en PHP que tengo tendría el LAMP incluido para la página de análisis de consumo. Por no decir que podría tener mi propia centralita de VoIP.

i want to ask, is it possible to reset the total energy using modbus serial in arduino? thankyou

https://gist.github.com/alphp/95e1efe916c0dd6df7156f43dd521d53#note-1

Total, export and import energy counters can erased writing 0 in total energy registers.

thankyou, it's worked on my arduino

I tested the DDS238-2 ZN/S with the current clamp. The refresh rate is quite slow (1-2 seconds)
and I noticed that the active power is sometimes reported with the wrong sign.
This issue can be reproduced with a resistive load backward though the current clamp:

Read   Active Power (address 0x000Eh)
-----  ------------------------------
1        0    // correct
2        0    // correct
// 40 Watts resistive reversed load is turned on .
3       31    // wrong, should be -31, not 31
4      -40    // correct
5      -40    // correct

This meter is therefore unreliable and cannot be used in a regulated feedback loop.

Indeed, it is not a reliable instrument for regulation.
But performing a reading/minute, valid values are obtained as a record.

Hello, I am also using the DDS238 ZN/SR. I am using QModMaster to communicate with the meter and a ethernet/modbus convertor DR302.

When I got the meter, ID=1. By using the read holding registers 0x03, I could read all the registers. And writing 0 or 1 to register 0x001A, I could switch the relay.

Then I wrote 0x2001 to register 0x0015, I lost all of the modbus communication. On the display is ID=000. The meter still works, it measures how it should do, but no communication. I have ofcourse also used the ID=0, the broadcast, but still no reply of the meter.

In QModMaster I have to increase the address with 1, so If I want to write to register 0x0015 I have to enter 0x0016. I check in the program the output and then it is correct.

Does anyone has seen this before? Can it be a problem with the QModMaster or does anyone how to set the address back to 1?

At the moment I don't have a RS232/RS485 convertor, it is ordered. Then I can use an Arduino to sent the strings and have every bit under control.

Greetings, Frans

Hello -
by accident, I also wrote 0 out in register 0x0015.
Now the gauge ID =0 and I can't fix it to anything else.
Is the recycle bin the only solution?

Hello, There is no limitation on what you write into the register, also not for the baud rate.  I did not find a way to reset the registers to the original value, also not by the supplier. Does your meter answer when you call it with ID=0, if not the recycle bin is the solution. ⁣Met vriendelijke groet, Frans Landsbergen​ Op 1 nov. 2023 16:05, om 16:05, MadsHHLund ***@***.***> schreef:

…

@MadsHHLund commented on this gist: Hello - by accident, I also wrote 0 out in register 0x0015. Now the gauge ID =0 and I can't fix it to anything else. Is the recycle bin the only solution? -- Reply to this email directly or view it on GitHub: https://gist.github.com/alphp/95e1efe916c0dd6df7156f43dd521d53#gistcomment-4746059 Unsubscribe from this thread: https://github.com/notifications/unsubscribe-auth/ADYO4DOAYPVQN7OWQZTXZV3YCJQK5BFKMF2HI4TJMJ2XIZLTSKBKK5TBNR2WLJDHNFZXJJDOMFWWLK3UNBZGKYLEL52HS4DFQKSXMYLMOVS2I5DSOVS2I3TBNVS3W5DIOJSWCZC7OBQXE5DJMNUXAYLOORPWCY3UNF3GS5DZVRZXKYTKMVRXIX3UPFYGLK2HNFZXIQ3PNVWWK3TUUZ2G64DJMNZZDAVEOR4XAZNEM5UXG5FFOZQWY5LFVA4TINZSGQYDEM5HORZGSZ3HMVZKMY3SMVQXIZI You are receiving this because you commented on the thread Message ID: <alphp/DDS238-2 ZN-S ***@***.***>

Okay recycle Bin.