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feat(plc4j/modbus): Updated the discovery to also find the unit-id fo…
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…r a modbus device.
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@chrisdutz
chrisdutz committed Feb 21, 2022
1 parent a5f3be3 commit 51657e8
Showing 1 changed file with 80 additions and 76 deletions.
156 changes: 80 additions & 76 deletions ...vers/modbus/src/main/java/org/apache/plc4x/java/modbus/discovery/ModbusPlcDiscoverer.java
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Original file line number Diff line number Diff line change
Expand Up @@ -99,25 +99,6 @@ private void executeDiscovery(CompletableFuture<PlcDiscoveryResponse> future, Pl
possibleAddresses = possibleAddresses.stream().filter(
distinctByKey(InetAddress::getHostAddress)).collect(Collectors.toList());

// Create the ModbusPDUReadDeviceIdentificationRequest
ModbusTcpADU deviceIdentification = new ModbusTcpADU(0, (short) 1,
new ModbusPDUReadDeviceIdentificationRequest(ModbusDeviceInformationLevel.INDIVIDUAL, (short) 0), false);
byte[] deviceIdentificationBytes = null;
try {
// Serialize the request to its byte form.
WriteBufferByteBased writeBuffer = new WriteBufferByteBased(deviceIdentification.getLengthInBytes());
deviceIdentification.serialize(writeBuffer);
deviceIdentificationBytes = writeBuffer.getBytes();
} catch (SerializationException e) {
logger.error("Error creating the device identification request", e);
}
if (deviceIdentificationBytes == null) {
future.complete(new DefaultPlcDiscoveryResponse(
discoveryRequest, PlcResponseCode.INTERNAL_ERROR, Collections.emptyList()));
return;
}
byte[] finalDeviceIdentificationBytes = deviceIdentificationBytes;

Queue<PlcDiscoveryItem> discoveryItems = new ConcurrentLinkedQueue<>();
possibleAddresses.stream().parallel().forEach(possibleAddress -> {
try {
Expand All @@ -129,69 +110,92 @@ private void executeDiscovery(CompletableFuture<PlcDiscoveryResponse> future, Pl

// Send the request to the target device
final OutputStream outputStream = socket.getOutputStream();
outputStream.write(finalDeviceIdentificationBytes);
outputStream.flush();

// Wait for a response.
final InputStream inputStream = new BufferedInputStream(socket.getInputStream());
byte[] responseBytes = null;
final long endTime = System.currentTimeMillis() + 2000;
while (responseBytes == null) {
// If we've got enough bytes to find out the size of the packet, try to check this.
if (inputStream.available() >= 6) {
inputStream.mark(6);
inputStream.skip(4);
byte[] packetLengthBytes = new byte[2];
int bytesRead = inputStream.read(packetLengthBytes);
inputStream.reset();
// Only if we really read 2 bytes, does it make sense to continue using it.
if (bytesRead != 2) {
continue;
}
final short packetLength = (short) (ByteBuffer.wrap(packetLengthBytes).getShort() + 6);
if (inputStream.available() >= packetLength) {
responseBytes = new byte[packetLength];
bytesRead = inputStream.read(responseBytes);
if (bytesRead != packetLength) {
responseBytes = null;

// Iterate over all possible unit-identifiers
int transactionIdentifier = 1;
for(short unitIdentifier = 1; unitIdentifier <= 247; unitIdentifier++) {
ModbusTcpADU packet = new ModbusTcpADU(transactionIdentifier++, unitIdentifier,
new ModbusPDUReadCoilsRequest(1, 1), false);
byte[] deviceIdentificationBytes = null;
try {
// Serialize the request to its byte form.
WriteBufferByteBased writeBuffer = new WriteBufferByteBased(packet.getLengthInBytes());
packet.serialize(writeBuffer);
deviceIdentificationBytes = writeBuffer.getBytes();
} catch (SerializationException e) {
logger.error("Error creating the device identification request", e);
}
if (deviceIdentificationBytes == null) {
future.complete(new DefaultPlcDiscoveryResponse(
discoveryRequest, PlcResponseCode.INTERNAL_ERROR, Collections.emptyList()));
return;
}
byte[] finalDeviceIdentificationBytes = deviceIdentificationBytes;

outputStream.write(finalDeviceIdentificationBytes);
outputStream.flush();

// Wait for a response.
byte[] responseBytes = null;
final long endTime = System.currentTimeMillis() + 100;
while (responseBytes == null) {
// If we've got enough bytes to find out the size of the packet, try to check this.
if (inputStream.available() >= 6) {
inputStream.mark(6);
inputStream.skip(4);
byte[] packetLengthBytes = new byte[2];
int bytesRead = inputStream.read(packetLengthBytes);
inputStream.reset();
// Only if we really read 2 bytes, does it make sense to continue using it.
if (bytesRead != 2) {
continue;
}
final short packetLength = (short) (ByteBuffer.wrap(packetLengthBytes).getShort() + 6);
if (inputStream.available() >= packetLength) {
responseBytes = new byte[packetLength];
bytesRead = inputStream.read(responseBytes);
if (bytesRead != packetLength) {
responseBytes = null;
break;
}
}
} else {
try {
Thread.sleep(1);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
if (System.currentTimeMillis() > endTime) {
break;
}
}
} else {
try {
Thread.sleep(10);
} catch (InterruptedException e) {
Thread.currentThread().interrupt();
}
if (System.currentTimeMillis() > endTime) {
break;
}
}
}
if (responseBytes != null) {
ReadBuffer readBuffer = new ReadBufferByteBased(responseBytes);
try {
ModbusTcpADU response = ModbusTcpADU.staticParse(readBuffer, true);
PlcDiscoveryItem discoveryItem = null;
if (!response.getPdu().getErrorFlag()) {
//final ModbusPDUReadDeviceIdentificationResponse identificationResponse =
// (ModbusPDUReadDeviceIdentificationResponse) response.getPdu();
// TODO: Unfortunately we need to find a device that's actually correctly responding to this request in order to implement this.
discoveryItem = new DefaultPlcDiscoveryItem(
"modbus", "tcp", possibleAddress.getHostAddress(), Collections.emptyMap(), "known");
discoveryItems.add(discoveryItem);
} else {
discoveryItem = new DefaultPlcDiscoveryItem(
"modbus", "tcp", possibleAddress.getHostAddress(), Collections.emptyMap(), "unknown");
discoveryItems.add(discoveryItem);
}
// Give a handler the chance to react on the found device.
if(handler != null) {
handler.handle(discoveryItem);
if (responseBytes != null) {
ReadBuffer readBuffer = new ReadBufferByteBased(responseBytes);
try {
ModbusTcpADU response = ModbusTcpADU.staticParse(readBuffer, true);
PlcDiscoveryItem discoveryItem;
if (!response.getPdu().getErrorFlag()) {
//final ModbusPDUReadDeviceIdentificationResponse identificationResponse =
// (ModbusPDUReadDeviceIdentificationResponse) response.getPdu();
// TODO: Unfortunately we need to find a device that's actually correctly responding to this request in order to implement this.
discoveryItem = new DefaultPlcDiscoveryItem(
"modbus", "tcp", possibleAddress.getHostAddress(), Collections.singletonMap("unit-identifier", Integer.toString(unitIdentifier)), "known");
discoveryItems.add(discoveryItem);

// Give a handler the chance to react on the found device.
if(handler != null) {
handler.handle(discoveryItem);
}
break;
/*} else {
final ModbusPDUError errorPdu = (ModbusPDUError) response.getPdu();
logger.info("Got error at address: {} with unit-identifier {} error {}", possibleAddress, unitIdentifier, errorPdu.getExceptionCode().toString());*/
}
} catch (ParseException e) {
// Ignore.
}
logger.info("Success at address: {}", possibleAddress);
} catch (ParseException e) {
// Ignore.
}
}
} catch (IOException e) {
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