cabat / mudbus Goto Github PK

What steps will reproduce the problem?

1. Send "Write single coil" request (FC=03)

What is the expected output? What do you see instead?

The coil gets written, but the response packet is corrupted.
See p.17-18 of http://www.modbus.org/docs/Modbus_Application_Protocol_V1_1b.pdf 
Expected response:
Function code (1 Byte) 0x05
Output Address (2 Bytes) 0x0000 to 0xFFFF
Output Value (2 Bytes) 0x0000 or 0xFF00
Actual response:
Function code (1 Byte) 0x05
nothing else.



What version of the product are you using? On what operating system?
v1.0

Please provide any additional information below.

Fix (lines 136-137 of Mudbus.cpp):
    ByteArray[5] = 6; //Number of bytes after this one.
    MessageLength = 12;

FC=0x0f
reads only multiples of 8bits from received packet. If you try to set 
any other number of coils, rest will be set to 0.

What steps will reproduce the problem?
1. write 111 to 3 coils starting from address XY
library will set 8 coils starting from address XY to 1110 0000

2. write 1111 1111 1 to 9 coils starting from address XY
library will set 16 coils starting from address XY to 1111 1111 1000 0000

What version of the product are you using? On what operating system?
1.0

I noticed an error in your library. Line 137 should be MessageLength = 12;
I was getting an error when writing to coils as the response was incorrect.

It appears that the library is leaking connection objects, leading to the 
eventual grind to a halt of the Arduino, which can only be fixed by a reboot.

I have a proposed solution, but I can't test it because I don't have modbus 
here. The colleague I researched this for does, but it will be a while before 
he returns to his home country to test it and tell me how it went. I wrote this 
based on the Arduino documentation, which says this: "The connection persists 
when the returned client object goes out of scope; you can close it by calling 
client.stop()."

Proposed solution:

diff --git a/Mudbus/Mudbus.cpp b/Mudbus/Mudbus.cpp
index 5c5356c..9340b02 100755
--- a/Mudbus/Mudbus.cpp
+++ b/Mudbus/Mudbus.cpp
@@ -36,6 +36,11 @@ void Mudbus::Run()
   // Client client = MbServer.available();
   // For Arduino 1.0
   EthernetClient client = MbServer.available();
+  if(!client.connected())
+  {
+    client.stop();
+    return;
+  }
   if(client.available())
   {
     Reads = 1 + Reads * (Reads < 999);

What steps will reproduce the problem?
1. mudbus dont send or receive data in pro mini board / w5100
2. tcp/ip working perfectly
3. ping and web works too

What is the expected output? What do you see instead?


What version of the product are you using? On what operating system?

1.02

Please provide any additional information below.