Hello everybody,
I am using PLC4X to poll 29 signals from a Siemens S7-300 device, all the
signals are of data type REAL. Every second I send a request to the PLC asking
for the values and then printing one of the values to the console:
PlcConnection conn =
driverManager.getConnection("s7:tcp://<IP>?remote-rack=0&remote-slot=1&controller-type=S7_300");
PlcReadRequest.Builder builder = conn.readRequestBuilder();
builder.addItem("value1", "DB.50.DBD0:REAL");
.
.
.
builder.addItem("value29", "DB.50.DBD116:REAL");
PlcReadRequest readRequest = builder.build();
while(true)
{
PlcReadResponse r = readRequest.execute().get();
System.out.println(r.getObject("value1"));
Thread.sleep(1000);
}
Everything works fine for some time, but after >50K requests or 8-12 hours with
the current polling rate at 1 second the code waits forever at the return value
from PlcReadResponse r = readRequest.execute().get() and doesn't continue. I
enabled Trace logging to see what's happening and every time this error occurs
I get the following error message:
12:56:48.107 [nioEventLoopGroup-2-1] TRACE o.a.plc4x.java.spi.Plc4xNettyWrapper
- Checking handler HandlerRegistration#65120 for Object of type TPKTPacket
12:56:48.107 [nioEventLoopGroup-2-1] TRACE o.a.plc4x.java.spi.Plc4xNettyWrapper
- Handler HandlerRegistration#65120 has right expected type TPKTPacket,
checking condition
12:56:48.107 [nioEventLoopGroup-2-1] TRACE o.a.plc4x.java.spi.Plc4xNettyWrapper
- Registration HandlerRegistration#65120 does not match object TPKTPacket
(currently wrapped to S7MessageResponseData)
12:56:48.107 [nioEventLoopGroup-2-1] TRACE o.a.plc4x.java.spi.Plc4xNettyWrapper
- Checking handler HandlerRegistration#65119 for Object of type TPKTPacket
12:56:48.107 [nioEventLoopGroup-2-1] TRACE o.a.plc4x.java.spi.Plc4xNettyWrapper
- Handler HandlerRegistration#65119 has right expected type TPKTPacket,
checking condition
12:56:48.107 [nioEventLoopGroup-2-1] TRACE o.a.plc4x.java.spi.Plc4xNettyWrapper
- Registration HandlerRegistration#65119 does not match object TPKTPacket
(currently wrapped to S7MessageResponseData)
12:56:48.107 [nioEventLoopGroup-2-1] TRACE o.a.plc4x.java.spi.Plc4xNettyWrapper
- No registered handler found for message
TPKTPacket[payload=COTPPacketData[parameters={},payload=S7MessageResponseData[tpduReference=0,parameter=S7ParameterReadVarResponse[numItems=19],payload=S7PayloadReadVarResponse[items={S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={66,61,-103,-102}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={66,65,51,51}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={65,-104,0,0}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={65,-120,0,0}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={65,-103,-103,-102}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={65,-127,-103,-102}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={65,-106,102,103}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={65,-96,0,0}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={66,-8,-26,-124}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={63,101,-95,48}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={0,0,0,0}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={63,-101,-114,57}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={68,122,0,0}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={65,-102,102,103}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={-66,109,9,123}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={0,0,0,0}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={-71,-67,-96,0}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={0,0,0,0}],S7VarPayloadDataItem[returnCode=OK,transportSize=REAL,dataLength=4,data={0,0,0,0}]}],errorClass=0,errorCode=0],eot=true,tpduRef=0]],
using default decode method
And this error message is the last thing that is printed to my console, it's
like the code is going into an infinite loop or something.
I used Wireshark to look at the packets coming from the PLC, I thought that
maybe there's a malformed packet or something that's causing the error message
above, but the packet looks exactly the same as the packets which are decoded
successfully. I have also experimented with the connection string, using with
and without the controller-type parameter, but without any difference.
I've also tried to increase the polling rate, requesting the values every
100ms, and that will cause the above error to appear after 1-2 hours so it
seems like the error appears based on the number of requests rather than some
time interval.
I have also tried to only poll for 1 signal instead of 29 but the same error
still appears after >50K requests.
I have a stable connection to my PLC during the entire time using an Ethernet
cable without any significant delay.
Anyone has any thoughts on what may cause this error?
I would be very grateful for any kind of answers since this is causing an halt
in my work.
Best regards,
Anton Engman
