Adress Twincat nModbus

[Benoît Lefebvre]

Hello everyone,

I have a small address translation worries.

I have a Beckhoff BC9000 controller card with a KL2114 (4 Digital Output), I have a Twincat System Manager solution and a PLC code. So far all is well.

I want to activate the DO via a C # program.

Currently I use the dll Twincat.Ads.dll with it I can "write" and activate my DO.

I would do the same but in ModBus.

Here is some code

MyObjectTwinCat = new TcAdsClient();

MyObjectTwinCat.Connect (Server, Port);

...

AdsStream ds = new AdsStream (1);

BinaryWriter bw = new BinaryWriter (ds);

ds.Position = 0;

MyObjectTwinCat.Write (0xF031, 0x20, ds);

What I do not find is the corresponding addresses and offsets in ModBus, in this case: 0xF031 and 0x20 and the Write method ...

MyObjectModBus.Write ... (address + offset, True);

Write with ... = WriteSingleRegister or WriteMultipleCoils or WriteMultipleRegisters or WriteSingleCoil?

I hope I was clear in my explanations.

In advance thank you very much for your help

Benoît

[MiguelS]

ModbusTCP Process Image

The ModbusTCP process image makes a fundamental distinction between digital and byte-oriented or word-oriented signals (Bus Terminals). Additionally, a distinction is made between inputs and outputs. The mapping table shows which Bus Terminals belong to which mapping.

Digital inputs	Digital outputs
Offset 0 ... 4095 Modbus function Reading 2 Writing: -	Offset 0 ... 4095 Modbus function Reading 1 Writing 5, 15

 

Analog/digital inputs	Analog/digital outputs
Offset 0x000 ... 0x0FF Modbus function Reading 3, 23 Writing: -	Offset 0x800 ... 0x8FF Modbus function Reading 3, 4, 23 Writing 6, 16, 23

This will be clarified by examples.

Example 1

BK9000
4 x KL1xx4
2 x KL2xx2
1 x KL9010

Inputs			Outputs
Modbus function	Modbus address/offset	Bus Terminal	Modbus function	Modbus address/offset	Bus Terminal
3 read	0x0000	4 x KL1xx4	3 read	0x0800	2 x KL2xx2
4 read	0x0000		1 read	0x0000
2 read	0x0000 - 0x000F		5 write	0x0000-0x0003
			15 write	0x0000-0x0003
			6 write	0x800
			16 write	0x800
			23 write	0x800

Example 2

BK9000
4 x KL1xx4
2 x KL2xx2
1 x KL1501
1 x KL3xx2
1 x KL4xx2
1 x KL9010

Inputs			Outputs
Modbus function	Modbus address/offset	Bus Terminal	Modbus function	Modbus address/offset	Bus Terminal
3, 4 read	0x0000..0002	KL1501	3 read	0x0800..0802	KL1501
			6, 16 write	0x0800..0802
3, 4 read	0x0003..0x0006	KL3xx2	3 read	0x0803..0x0806	KL3xx2
			6, 16 write	0x0803..0x0806
3, 4 read	0x0007..0x000A	KL4xx2	3 read	0x0807..0x080A	KL4xx2
			6, 16 write	0x0807..0x080A
3 read	0x000B	4 x KL1xx4	3 read	0x080B	2 x KL2xx2
			4 read	0x080B
4 read	0x000B		1 read	0x0000-0x0003
2 read	0x0000 - 0x000F		5 write	0x0000-0x0003
			15 write	0x0000-0x0003
			6 write	0x80B
			16 write	0x80B
			23 write	0x80B

h 

[Benoît Lefebvre]

Hello , thank you for your reply and sorry for the delay , I was on leave.

You talk to me much of the Modbus protocol , but I try to use the <Nmodbus> project and I do not know what function used: "Write with ... = WriteSingleRegister or  WriteMultipleCoils or WriteMultipleRegisters or WriteSingleCoil ? " and at what offset .

I would activate an output on a KL2xx2 (or 4)

Again thank you to you and sorry for my english

Benoît