Siemens OPC server refreshrate

Hi

Im using SIMATIC NCM v 6.3 and a S7-400
I have written an OPC Client in visual basic.

My comminication between the PLC and the OPC server is up and running.
Inside the PLC I have used OB35 wich is called every 100ms. In this ob I constantly read DB200.DBW1 and do +1. And when it reaches 1000 I reset it to 0 and start over again. So basicly I have generated a saw toothed signal with a frequency of 10Hz

When I use OPC Scout I can see that the value of my Word changes at the expected rate.

So now I start my own OPC Client and I can read the value of this word. But it only refreshes every 1000 ms ( Every second ) instead of every 100 ms. So instead of
1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19 20,21
i see
1.................................,11..................................................,21....

So I decided that my program would somehow not be fast enough.I run a seperate free OPC Simulation server. In this server there is a value present that is ramped just like I have made with my PLC. So I check this... I reads at the expected rate. 10 values a second. Even better the maximum speed I reached was 60 values a second. I could measure this because I log this in an acces database.

So I thought what happens if I use a different OPC client... I have installed a different OPC Client and I tried reading the same Word. And I can see it changing faster than once a second. Im not sure if it is 10 times a second but at least it is faster than with my own program.

So this time I rewrote some of the code in my program. Until now I used a routine that runs every time the data changes. I replaced it with a routine that runs every 100 ms. What I get now is this...

1, 1, 1, 1, 1, 1, 1, 1, 1, 11, 11, 11, 11, 11, 11, 11, 11, 11, 11, 21, 21, 21, 21 ,21, 21, 21, 21, 21 ,21

I get 10 exactly the same values in second 1 and in second 2 I get 10 times my old value +10

So now im puzzled. I can read fast enough but it looks like the siemens OPC server only gives me a change once a second. And to other programs it does that faster. So in my view it either is some setting in the server that I missed that allows some methods quicker acces than other methods.

Can anyone help me?

Hereby the server LOG

Im running 2 clients

One with groep2
and one with a groep called ss ( for no reason btw)

Hi Obeleh,

I would contact Customer Support, they have specialists to analyse this....

I am sure you will get this solved there.

Stay calm.

New question published by junaidstar is split to a separate thread with the subject OPC XML SOAP Error.

Best regards
Jen_Moderator