S7-1200 over SCADA driver S7A - same values in data monitor

Hello!

I am beginner in PLC world, also in SIEMENS PLCs. I managed communication over private network. Now I have a problem that I get same values on all inputs. Picture below shows my configuration of driver and data monitor. First picture shows when input I0.0 is in state 0. Second picture shows values when input I0.0 is in state 1. Physically on PLC only input I0.0 is forced to 1, input I0.1 stays 0. But data monitor shows both inputs as state 1. Where is problem? Third picture shows simple PLC program on my PLC. Please help. Thanks in advance!

Is that the correct addressing? It is on the PLC side, but is it on the S7A side?
Do you have other tags that are working with the dot notation?

I just tried with other notations according to S7A Help. I wrote IB0U, which means Input Bytes at address 0, unsigned. It detects all inputs, but shows these values for physical inputs when turned to state 1: I0.0: 1, I0.1: 2, I0.2: 4 and so on. If I change first two inputs to state 1, it adds values (1+2=3). There must be some wrong addressing setting. I couldn't find anything else helpful in Help... I hope there is someone understanding what is going on.

I wonder if it discards the dot and is looking for something else?



Can you perhaps try with a / separating the Input word from the bit? I0/1??

No, it doesn't help, still same problem. I will try creating Data block in PLC program and then address inputs with Data Block (DB) as memory area in S7A driver. I've seen people doing it this way.

I created Data Block in PLC program using different addresses. I created tag with address DB3.DBX0.0 and then tag with address DB3.DBX2.0. With this addressing (creating variables in data monitor in S7A driver) it is working fine and I can see seperate values for each tag. Then I tried adding tag with address DB3.DBX2.1. Tags with addresses 2.0 and 2.1 have same values again but tag with address 0.0 stays as it is. Looks like addressing is causing problems. It is not hard to have different addresses in data blocks. But what about physical inputs in PLC? I have only built-in physical inputs without using additional modules, so addresses of inputs are I0.X. Why are these last bits causing problems? Somehow I managed it with data blocks. But why are then inputs, outputs, flags available in S7A driver? Can someone explain what is problem and what am I doing wrong? I have seen people using addressing I0.0, I0.1 and it worked fine for them.

Thanks in advance!

It looks like you haven't quite solved your problem if the DB bits 0 and 1 aren't correct. Otherwise you would be reading a byte for each bit you need. That is a massive drop in efficiency, from my point of view.

I haven't used S7A before... and am now glad I didn't. :/

Yes. I tried installing S7A driver v1.52 on my virtual machine where I also have demo version of iFIX 5.8. Everything works great!!! I can read inputs, outputs, flags and everything for seperate bits. So I am shure I am addressing bits correctly, there has to be some issue in driver itself.

Thanks for replies!

Junk it and use something like Kepware, S7A is not very stable not user friendly, had it fall over many times is cumbersome to use when I upgraded to Kepware it ran without problems for 5 years and still would be if the plant was still in use.

Wow, just tried Kepware and it's awesome!!! Works everything at first try. I will present Kepware at my company so we will decide what to use. We will need license, that's why.

I've been in contact with Siemens support from Slovenia. We are trying to configure OPC UA server on PLC side and then retrieving data with SIMATIC NET software. But it drives me crazy. After 4 days I still can't get data from PLC. On the other side Kepware was installed and configured in 15 minutes, working as a charm! Thanks again!

No problem I have no association with Kepware & there are others (but I believe most of them are re-badged Kepware) To be honest a number of Scada systems have their own drivers built in but these are often a nightmare to configure, for around £650.00 you can get a single driver or pay around £1500.00 and get a complete suite of drivers (useful if your plant has a lot of different PLC's). The best thing is you can try before you buy.

IGS from GE is "last year's Kepware"... if I remember right, only Kepware has the ability to deal with the S7-400 redundant CPU's though.



I am glad that I just upgraded IGS instead of taking a leap for S7A, which as far as I know is also a paid product.