Recommended PG/PC Interface for Profibus DP ?

I'm planning on equipping a desktop computer to communicate with Siemens POSMO A integrated servodrives over a Profibus DP network. The network master will not be a Siemens PLC; instead it will be a third-party network linking device.

I described the system in this previous thread [Link] and got some excellent advice from our colleague JRW.

I want to ask what the best modern PC to Profibus DP interface is that will work with a system that does not have an S7 CPU as the Profibus DP master.

I think the CP5611 PCI card might be my best bet; it should be compatible with the PCI slots on the Dell Optiplex tower PC that the customer has specified as an engineering workstation and HMI. The "Set PG/PC Interface" feature in SimoCom A software lists it explicitly as a supported interface.

There are USB devices for this purpose too (they appear to be just called "PC interfaces" in the software) and those would seem to be more portable and flexible.

But I have read that the older 6ES7972 device only supported data rates up to 1.5 Mb/s and needed 24V power from the S7 CPU (and I think that would apply also the PLCCables.com alternative).

Does anyone have experience with the modern 6GK1571 USB device (aka CP 5711) connecting to a Profibus DP network with no S7 CPU ? The technical information I can find on that suggests it can run at up to 12 Mb/s but doesn't say anything about needing power from an S7 port and it appears to have screw terminals to accept power. It is also named in the SimoCom A software as a supported interface.

I don't know what data rate this Profibus DP network is actually running at: when we do competitive bids like this, the customer often refuses to answer questions that weren't included in the bid spec, so that all bidders must account for the same degree of uncertainty. I know the network has as many as 72 nodes on one DP port, but they're connected with repeaters so there fewer than 32 nodes per segment and the Turck repeaters will handle 12 Mb/s.

Hi Ken.

Take a look at the Helmholz NET Link PRO.
Part number: 700-884-MPI21.

Thanks for that recommendation ! The ISO on TCP (RFC 1006) driver does appear in the available selections.

Now to figure out how to buy one Stateside.... it looks like they sell them through an Helmholz Sales. It might be that Hilscher North America sells the same item as well.

I got mine from some place in Texas.
Distributor but I forgot the name.
San Antonio maybe?

or maybe this:
Online store.
https://helmholzsales.com/collections/s7-communications

Do you use yours with a non-S7 Profibus DP network ?

It certainly looks like it will work, but I'm treading some unfamiliar ground with this multivendor project and I'd appreciate hearing any confirming evidence of being able to use this with S7 engineering tools that don't actually include an S7 controller.

I've used it with some Wago stuff a long time ago.
I have been using it mostly with Siemens as it is a "do-it-all" with older hardware when it comes to going online and such.
If it helps any, the gateway can be setup as a Master on the bus.
I assume this will work in your case but.......
I'm sure there's white papers and such on it and FAQs, you may get lucky
and find the answer on there.
Sorry If I cannot be of any help.

" The connector casing has an integrated PG socket, which permits connection of further devices. NETLink® PRO Compact permits conversion from TCP/IP to MPI/PPI/PROFIBUS with a maximum of 32 simultaneous links, and supports the communication to passive participants by activating the switchable Single-Master function"
from their sales page.

Funny thing is I cannot locate any PDF's, white papers and such on their site now.
Used to be quite a few a while back.
Or maybe I am looking at the wrong site.

I guess you have to go to their German site
https://www.helmholz.de/
RFC 1006 examples available.

Let me sum it up as I understand the setup:
There is a Siemens Posmo drive as a slave on Profibus.
And there is a 3rd party Profibus master for the Posmo drive amongst others.
The PC is for commisioning and troubleshooting the Posmo drive via the Simocom software.

I dont have experience with Posmo drives, but I do have experience with other Siemens drives on Profibus and Profinet.
If Posmo drives work the same as other Siemens drives, then I am sure that the PC do not have be the master for the Posmo drive, but it must be a master on the Provibus network.
This means that the PC and the 3rd party master are masters on the same network which is called multi-master. This in turn means that both PC and 3rd party master must know of each others existence, when setting up the Profibus bus parameters. The pressence of additional masters in a Profibus network affects the calculation of the socalled Target Token Rotation Time.
So this means that someone has to be responsible for calculating the TTR. If this was a 100% Siemens project, then the Siemens software would handle this for you. Since this is a mix of Siemens and 3rd party devices then there may be some manual tweaking. It may be as simple as telling the configuration tool that there exist one or more masters that are not part of its own configuration.

Another complexity is that the communication between the PC and the drive wont exactly be pure Profibus DP. We can see that by the reference to the socalled "PG/PC Interface".
So that again means that the adapter must be one that supports PG/PC Interface.
Of course the Siemens adapters do this, and maybe even the Helmholz adapter. It may be a little tricky to get the Helmholz adapter setup fot the Simocom software.

Beware, the CP5611 is for PCI, not PC Express which is the current standard in PCs.

Ken Roach said:

Does anyone have experience with the modern 6GK1571 USB device (aka CP 5711) connecting to a Profibus DP network with no S7 CPU ? The technical information I can find on that suggests it can run at up to 12 Mb/s but doesn't say anything about needing power from an S7 port and it appears to have screw terminals to accept power. It is also named in the SimoCom A software as a supported interface.

Click to expand...

USB A2 is USB powered so doesn't need 24V or anything like that. No screw terminals on that one that I can remember. I use it all the time to hook up to older S7-300 systems.

You know, profibus is just serial RS485 communication so when establishing communication and support for different devices it's all a question of software. Except transmission rate - which the latest version of the USB A2 interface supports up to 12 Mbit.