aldas
commented
5 years ago -
by default unitID/SlaveId is 0. Maybe you need to use different slaveID ala 1
$slaveID = 1; $packet = new ReadHoldingRegistersRequest($startAddress, $quantity, $slaveID); -
maybe you need to wait a little before reading change from using
sendAndReceiveto$connection->connect()->send($packet); usleep(100000); // wait 100ms $binaryData = $connection->receive(); -
use wireshark to see what
Modbus Slave Softwaresends and compare it to what is library sends.
gupta-shrinath
Hi There Thanks for the library and I am new to Modbus protocol so this question might be naive. I used the library with Modbus Slave Software and it worked flawlessly but when I connect my laptop to actually devices an exception is thrown response packet to be null. I have 2 devices connected to the RS485 to Modbus TCP Converter and the setting for the devices are Baud Rate 9600 bits/second Data Size 8 bits/character Parity Odd Port Number502 Network Protocol TCP RS485 to Modbus TCP Convertor IP is 169.254.205.239 And here is my code `<?php include 'database.php'; use ModbusTcpClient\Network\BinaryStreamConnection; use ModbusTcpClient\Packet\ModbusFunction\ReadHoldingRegistersRequest; use ModbusTcpClient\Packet\ModbusFunction\ReadHoldingRegistersResponse; use ModbusTcpClient\Packet\ResponseFactory; require DIR . '/vendor/autoload.php'; //$server_ip = getHostByName(getHostName()); $server_ip = '169.254.205.239'; //echo "Server IP Address is: $server_ip"; $connection = BinaryStreamConnection::getBuilder() ->setPort(502) ->setHost($server_ip) ->build(); $startAddress = 40043; $quantity = 10; $packet = new ReadHoldingRegistersRequest($startAddress, $quantity); //echo 'Packet to be sent (in hex): ' . $packet->toHex() . PHP_EOL; try { $binaryData = $connection->connect() ->sendAndReceive($packet); //echo 'Binary received (in hex): ' . unpack('H*', $binaryData)[1] . PHP_EOL; /**
@var $response ReadHoldingRegistersResponse / $response = ResponseFactory::parseResponseOrThrow($binaryData); // echo 'Parsed packet (in hex): ' . $response->toHex() . PHP_EOL; // echo 'Data parsed from packet (bytes):' . PHP_EOL; print_r($response->getData()); $array = $response->getData(); $query = "SELECT FROM holdingregister WHERE id='1' ;"; mysqli_query($con,$query); $count = mysqli_affected_rows($con); if($count>0) { $sql = "UPDATE holdingregister SET register1 ='$array[1]' , register2 = '$array[3]' , register3 = '$array[5]' WHERE id = 1"; mysqli_query($con,$sql); } else{ $sql = "INSERT INTO holdingregister(id,register1,register2,register3) VALUES ('1',$array[1],$array[3],$array[5])"; mysqli_query($con,$sql); }
/ foreach ($response as $word) { print_r($word->getBytes()); } foreach ($response->asDoubleWords() as $doubleWord) { print_r($doubleWord->getBytes()); } // set internal index to match start address to simplify array access $responseWithStartAddress = $response->withStartAddress($startAddress); print_r($responseWithStartAddress[5000]->getBytes()); // use array access to get word print_r($responseWithStartAddress->getDoubleWordAt(5001)->getFloat());/ } catch (Exception $exception) { echo 'An exception occurred' . PHP_EOL; echo $exception->getMessage() . PHP_EOL; echo $exception->getTraceAsString() . PHP_EOL; } finally { $connection->close(); }`