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SRTP Protocol
Does GE have any documentation on the SRTP Protocol?

Does GE have any documentation on the SRTP Protocol? Our company is very interested in writing a driver for GE9030 PLCs with CPU364 using SRTP. We currently have over 15 of these PLCs and are now purchasing 5 more. We have written an HMI using VB6 but using a purchased driver to communicate with PLC. Any books or support for the protocol?

By Prasanth Gopalakrishnan on 2 February, 2004 - 8:47 am

You might want to contact GE Directly or if you post online, GE Support will give you details of the SRTP protocol. I think, you will have to sign an NDA and the likes. Also, i do not think they have manuals and books for the same. What they have is some sample code so that you can connect over SRTP from any 3rd party systems over sockets.

GE Also have host communication toolkits, which provide you with TCP/IP interface, with which you could integrate the PLC to your application.

Sincerely,

--------------------------------------
Prasanth Gopalakrishnan
Kalki Communication Technologies Private Limited
Phone: 91-80-25721263/4
Mobile: 91-98454 50872
Fax: 91-80-2572 5473
E-mail: prasanth@kalkitech.com
Web: http://www.kalkitech.com

By Automation Linse on 2 February, 2004 - 9:49 am

I do not believe GE considers that public knowledge. However you can get a feel for the basic "messages" moved by reviewing the SNP document now available on-line:

http://www.gefanuc.com/infolink/manuals/gfk0529c.pdf

Then do a quick "Ethernet sniff" of a GE tool using SRTP - ideally pop open a data window in the GE programming tool and you'll see exactly what you need. It is a common design - a fixed header before the variable-sized "message". First message exchange will be a "connect" request & response. After that just data poll/responses. Main difference between SNP and SRTP is SNP needs to chunk messages up into many small "text buffers", while SRTP can use a full sized TCP packet (up to 65K?) data.

- LynnL, www.digi.com

By Prasanth Gopalakrishnan on 3 February, 2004 - 11:03 am

I do not think SRTP uses 65K packets. Its packet size is around 1K. If you are using it for a specific project using GE PLCs, i think GE would give out the sample code for SRTP after you sign an NDA. You may check with GE online support.

Sincerely,

--------------------------------------
Prasanth Gopalakrishnan
Kalki Communication Technologies Private Limited
Phone: 91-80-25721263/4
Mobile: 91-98454 50872
Fax: 91-80-2572 5473
E-mail: prasanth@kalkitech.com
Web: http://www.kalkitech.com

Just curious, why do you want to write a driver for this when there are many OPC servers available for the GE PLCs? We have used the ethernet driver from kepware for a couple of years now without issue. It seems a little crazy to write a driver when one can be had off the shelf. Have you tired theirs, it seems fast and we have never had an issue with ours and we have 7 copies on different machines. Their web site is http://www.kepware.com.

If you are still looking to do it by hand I think you will have to call GE and see if they will give you the data as others have said here.

By Curt Wuollet on 4 February, 2004 - 10:32 pm

Sometimes it's good to have a driver you know something about. Or one that doesn't restrict your choices or bind you to OPC only. Well over half the uses I have for PLC comms wouldn't be well served by an OPC driver. I had no luck getting _any_ info on SRTP from GE. Of course they knew I would roll my own with real diagnostics that would show who missed a slot or dropped a packet.

Regards

cww

By Paris Rossano on 2 February, 2015 - 5:41 am

Good morning.

I've seen your conversation while I was trying to get some information regarding GE SRTP protocol.

Would you be so kind to tell me if you realized such driver?
I'm interesting in writing a SRT driver too, so any information would be precious.

Best reagrds
Rossano Paris

> Sometimes it's good to have a driver you know something about. Or one that doesn't restrict your choices or bind you
> to OPC only. Well over half the uses I have for PLC comms wouldn't be well served by an OPC driver. I had no luck
> getting _any_ info on SRTP from GE. Of course they knew I would roll my own with real diagnostics that would show who
> missed a slot or dropped a packet.

>Regards
>cww

Hello,

We created a driver for SRTP and it was not very hard. I do not recall but, Wireshark might decode packets. I could never find a GE document on SRTP.

You could look at LibOpenSRTP for information.

Good luck,

Mark
http://www.peakhmi.com/

Rossano:

> I'm interesting in writing a SRT driver too, so any information would be precious.

Depending on your situation I would not spend my time writing a driver if an off the shelf solution was available. Automated Solutions (http://www.automatedsolutions.com/) has a driver I have had very good luck with.

I am still writing code in VB6 and just last year I completed a cam milling application with a full HMI and a data trender running simultaneously. The amazing part is the trender gathers 16 floating point (real) numbers ever 15 milliseconds while cutting a cam with no noticeable affect on the HMI.

Automated Solutions was also very cooperative in adding a feature to transfer %W registers. This feature helped in transferring the cam profile data and is now part of their standard offering in both ActiveX and .Net drivers. They also have an OPC driver but I have no experience with it.

Bob Krause
Krause Engineering, Inc.
Bob@KrauseEngineering.Net

I had an interface written years ago to connect a GE turbine control system to a DCS via SRTP (could have tried GSM as well, but decided against it at the time). The DCS vendor was able to get all the pertinent information from GE to make this happen, so it was available......around 2001 anyway. Now days I simply go with OPC!

Hello,

>I had an interface written years ago to connect a GE
>turbine control system to a DCS via SRTP (could have tried
>GSM as well, but decided against it at the time). The DCS
>vendor was able to get all the pertinent information from GE
>to make this happen, so it was available......around 2001
>anyway. Now days I simply go with OPC!

I am looking for information about the communication between Rx3i PLC and a computer. I want to develop my own driver only to read registers. I need help. I don't want to pay.

By Bob Peterson on 12 March, 2018 - 3:36 pm
1 out of 1 members thought this post was helpful...

> I am looking for information about the communication between Rx3i
> PLC and a computer. I want to develop my own driver only to read
> registers. I need help. I don't want to pay.

=========================================

GE advertises that the communication protocols for this PLC are "Open". That implies to me that it should not be especially hard to find the protocol. That does not mean it will be an easy task to develop and test the software. Just that the information is probably not all that hard to come by.

As I recall, that processor also supports Modbus/TCP, which should be a lot easier to deal with since I believe there is open source code for Modbus/TCP available.

To be candid, even if there is software available that you could get for free and modify to do what you want the time spent getting it for free and the time spent updating and maintaining it over the years might well make it not much of a bargain.

--
Bob
http://ilbob.blogspot.com/

I have asked to GE but the protocol isn't open. For Modbus TCP, I think that I must pay a new card.
So at this moment I have no solution.
It is incredible, if you can help me, I would be very happy.

By Fred Loveless on 20 March, 2018 - 9:57 am

At this point you best option is probably going to be to find product that can communicate with that protocol. There are several OPC Servers out there that support multiple client/server interfaces. For this protocol I can think of 4 right of the top of my head:

GE has an embedded interface.
Kepware's KEPServerEX (does OPC DA, UA, DDE, Suitelink, RST, MQTT)
Software Toolbox Topserver (does OPC DA, UA, DDE, Suitelink, RST, MQTT)
Matrikon OPC Server

Automated Solutions offers a GE SRTP Ethernet driver that supports RX3i, RX7i and RXi natively (English tag names, rack and slot specification, etc.).

https://automatedsolutions.com/products/dotnet/ascomm/ge.srtp.asp

Price is $249 for one PC. Or consider a development license for non-commercial runtime-free deployment to multiple PCs.

I am very surprised that we can't find the a free driver, like Modbus TCP. You have perhaps an idea where I can find it without to pay.