Most common Protocol

Hello, can anyone with experience in industry tell me, which
protocol is most common, for Scada?

Thanks

Not sure which is more popular, Modbus or HART. Personally I like Modbus best of all for an industry-wide recognized and easy to implement protocol.

Hello,

It depends on which industry. As a general rule, I would say MODBUS RTU, TCP/IP.

MODBUS seems to be in more industries than most. It is easy to implement, so vendors tend to add it as either their second or even first option.

manin said:

Hello, can anyone with experience in industry tell me, which
protocol is most common, for Scada?

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You might need to define your question more precisely. Are we talking 'most common' for new systems or for systems currently in use.

Why do you want to know?

Asking which is 'most common' currently in use will skew the results to older technology. If your reason for asking is to build a new system you could end up building with antiquated technology.

My experience shows that the vast majority of installed systems use an older fieldbus technology (Modbus, DeviceNet, Profibus). New systems are roughly split evenly between traditional fieldbus and industrial Ethernet networks.

As already mentioned, what 'industry' are you talking about.

Where are you talking about?

In Europe, Profibus seems more common that Modbus. In the US, it looks
Modbus is falling to CIP. The Far East is the wild, wild, west when it comes to protocols. None show much of a lead.

A lot depends on which PLC you use. Schneider generally use Modbus, AB and Omron are generally using Ethernet I/P, Siemens one of the forms of Profibus. The latest one I have been, and still am, involved in is using Omron FINS plus Modbus TCP.

in my experience the most common is Modbus. For serial it is Mobbus RTU and for Ethernet it is Modbus TCP

Siemens uses it's own protocol. When it comes to the Scada systems, the protocol maybe on top of Ethernet/IP/TCP, only Ethernet without IP, RS485/Profibus or RS485/MPI, always the same.

In Germany I would guess more than 3/4 of all automation systems are Siemens based systems.

Electrical distribution uses DNP and the more recent IEC xxxx protocols.

Thomas_v2 said:

In Germany I would guess more than 3/4 of all automation systems are Siemens based systems.

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You unfortunate souls.

I would say there are two aspects. The OP said the most common protocol for SCADA. Well i think your controller will define this in most cases. Most software packages have drivers for the various types of controllers. Personally i prefer to use Kepware or Topserver as a middle man as their drivers work tonnes better in most cases. You then interface via OPC from IOServer software (Kepware and Topserver) to the SCADA package.


Then there is the PLC to intelligent devices (drives , instruments, ect). Again i think the best choice for each design,would depend on the controller and intelligent devices that you use . There are cases where you might have convert Profibus to Modbus ect. But it all depends on your hardware.

If you are really asking "Which protocol is the most important to study", then I would answer "OPC".
OPC is not really a protocol itself, but it is indeed invented in order to have a standardised interface between PC based software and plant devices such as PLCs.
In short, OPC servers takes care of the myriad of different protocols and presents it in a common understandable way for the software application (the OPC client) such as a SCADA.

RET said:

You unfortunate souls.

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Can I ask why you say this? Do they make bad products?

isiah_s said:

Can I ask why you say this? Do they make bad products?

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I can't speak for him, but it's popular in the US to prefer AB products over most others, and (often at least partly jokingly) make snide remarks about alternatives.

Until very recently, Siemens products were designed mostly for the European market. People over there mostly use PLCs very differently. Programmers prefer to use FBD instead of LAD, and typically do their "real" work in STL(IL) or SCL. My understanding is that the typical programmer (in germany at least) has the educational equivalent of a US masters. Over here, half of the programmers I meet are former electricians with most schooling from hard knocks. Different experience, different preferences.

Siemens HW is (generally) high quality, and the software is powerful. What it historically hasn't been, is user friendly (especially to someone expecting it to work like an AB system).

The new HW/SW is way better. It removes a lot of the stupid roadblocks the old software had. However, the experience people usually remember is that one job they did 5 years ago, where they had to learn the software on the fly and didn't have time to get training or even ask for help. That wouldn't give anyone a good impression of anything.

mk42 said:

My understanding is that the typical programmer (in germany at least) has the educational equivalent of a US masters. Over here, half of the programmers I meet are former electricians with most schooling from hard knocks.

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That's a mighty big brush you just stroked.