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Siemens S7-300 to OPC Server - Kepware, Mertz

Siemens S7-300 to OPC Server - Kepware, Mertz

Siemens S7-300 to OPC Server - Kepware, Mertz

We have a simple system with about 131 tags. And require a fast up date to our HMI.

We have the following hardware

Siemens CPU 315
Siemens RS232 -> MPI interface
Kepware OPC Server software
Cimplicity Plant HMI

What I have found is that with the 131 tag we only get 5 tags updated a second. Therefore this makes the HMI graphics jumpy  as we are trying to measure position on a vessel.

Q1)If we were to change the Siemens RS232-MPI link to  the siemens MPI-> PCMCIA adapater would there be an increase in the ammount of refreshes a second I get.


RE: Siemens S7-300 to OPC Server - Kepware, Mertz

On your MPI network how many nodes do you have? I see you are only pulling 131 points but is there other traffic. You may need to increase the max number of retries. Also you may need to lengthen your delay before time out. I have had to increase this as high as 10 at 3 Sec.
Also have you started quick client to verify point’s status?

Are you using the PG programming device or the PG HMI adapter? Depending on you Ver. of  the device not all PG devices will work as HMI interfaces.

Although I have friends that claim the PCMCIA MPI is faster I my self don't see it after all MPI@19.2K is MPI@19.2K. But if your 315 has an DP port that is much faster. And would recommend a PCMCIA DP for best performance.

RE: Siemens S7-300 to OPC Server - Kepware, Mertz


MPI  can go up to 187.5 K with a PC MPI board.

Are you using Protool/pro for HMI? - ther is a tag update rate, there.
What OS on your PC? From what i know there is a time frame limit on windos.

For sure Profibus DP will increase your communication speed - up to 12M instead of 19.2 K - PCI or  PCMCIA.
e.g. CPU 315-2DP


RE: Siemens S7-300 to OPC Server - Kepware, Mertz

To answer all the Pervious questions in one.

There is only one node on the MPI network and we are using a laptop as the "PG" not a siemens system but a panasonic toughbook(High Spec) running Win2k. I have verified the points in the quick client and they all work but very slowly.
I think this is due to kepware "Polling" each tag to see if it has changed and then updateing if it has or ignoring if it hasn;t. Then moving on to the next point.

My understanding was that the pcmcia MPI Link could run far faster and could be set at 1.5Mbs or Higher. Due to it not being limited by the rs232 interface on the PC but rather being connected straight to the PCI bus.

and the CPU we are using doesn't have a DP interface. The Laptop is running Win2k.

Hope this additional Information Helps.


RE: Siemens S7-300 to OPC Server - Kepware, Mertz

Yes the CP5511 pcmcia adapter will be faster. Your limitations with your pg/pc interface is limited to 19.2k or 38.4k depending on the switch on your adapter. With the CP5511 you will get faster updates, but I would sugest contacting your local distributor to borrow one first to see if the improvement is worth $1500.00.

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