preferred communication protocol for scada

[johnny78]

hello Guys
Im working on light control system uisng microcontroller & communication system to control on Lan network(something like scada)
i have tested Arduino UNO with ENC28J60 ethernet module & it works on my network
i have some knowledge with visual basic But which protocol you suggest to use on a network so i can access my app easily?

Thanks
Johnny

 

[KlausST]

Hi,

Do you want to be compatible to anything?
Or do you want your own protocol? Then any UDP based protocol may be the simplest.

Klaus

 

[FvM]

MODBUS/TCP ?

 

[johnny78]

MODBUS/TCP ?

what do you mean?
i will send data from ATmega through Ethernet Module to the Router or switch
so i can assign an ip which i can access it with my visual basic app

why i need modbus ?

 

[KlausST]

Hi

why i need modbus ?

You asked for a suitable protocol. Modbus/TCP surely is.

But you are free to choose it or not.

Klaus

 

[FvM]

I answered the question in the thread title. MODBUS is one of the preferred protocols for SCADA. You can test your implementation against existing server and client devices and test tools. You might also reuse existing MODBUS code for your application.

If you are designing a commercial product, a MODBUS interface guarantees that it can be used with almost any control system.

 

[johnny78]

I answered the question in the thread title. MODBUS is one of the preferred protocols for SCADA. You can test your implementation against existing server and client devices and test tools. You might also reuse existing MODBUS code for your application.

If you are designing a commercial product, a MODBUS interface guarantees that it can be used with almost any control system.

Hi

You asked for a suitable protocol. Modbus/TCP surely is.

But you are free to choose it or not.

Klaus

another question related to TCP
i have connected the Ethernet module(ENC28J60) to Lan port of the router & connected the other lan port to the Laptop & the example work (with disconnected internet) so i can open the browser & enter the assigned IP & get the page which controls the Arduino
the problem is when i use a Switch or Hub instead of the router that its not working
i was looking for reason but i couldnt
any idea to look for will be great

Thanks

 

[KlausST]

Hi,

IP address, network mask?

Klaus

 

[johnny78]

Hi,

IP address, network mask?

Klaus

Hi
in my Arduino sketch i have configured this

static uint8_t mac[6] = {0x54,0x55,0x58,0x10,0x00,0x24} 
static uint8_t ip[4] = {192,168,1,200}
static uint16_t port = 80;

client.setup(mac, ip, port)

when using my router lan ports to connect between the Ethernet module & the laptop to open the browser with the assigned ip(192.168.1.200)
it open the html page which written in the Arduino webserver Sketch & everything is ok
BUT when i connect 10/100Mbps Desktop switch instead of the Router it show lan Leds but no real connection
the Switch has no ip config as i see
So i think i must add something in my sketch to be compatible with the switch

Thanks

 

[KlausST]

Hi,

Afaik every ethernet device needs to have an ethernet address and an ethernet subnet mask...at least for TCP..

Maybe at start up it receives one from a DHCP server....but if there is no DHCP server it should have a default address.

I'm not an ethernet specialist....
So please read documents about basic ethernet communication. (At least this is what I'd do)

Klaus

--- Updated May 17, 2021 ---

Hi,

Important: MAC address needs to be unique. If you have two or more devices programmed with the same MAC address in your net, then it may cause problems.

Now it depends how your device is programmed and how the switches/routers work.

there are several scenarios possible
* if there is no DHCP server in your net, then I expect the device to keep the "192.168.1.200".
* if there is a DHCP server in your net then it may or may not overwrite your "192.168.1.200". Depending on your device setup.

*****
but the problem may also be on the laptop side.

When you can connect to the device: what is the laptop´s ethernet address and subnet mask?
(Windows: DOS prompt. "ipconfig")

Is it different when you are not able to connect to your device?

*****
What happens when you directly connect the notebook with the device? without any other ethernet connection.

Klaus

 

[johnny78]

Maybe at start up it receives one from a DHCP server....but if there is no DHCP server it should have a default address.

thanks Klaus
its the DHCP server
i forgot to assign an ip to the laptop

 

[KlausST]

Note: The forum system gets confused when posts are edited while members reply.
The chronological order was:
* post#1 ... post #8
* first version of post#9
* my reply post #10 (on your post#9)
* edit of post#9
* my reply on the edited post#9 (which the forum software automatically merged to post#10)

Klaus