Step7 MPI Connection instable

I have quite a nasty problem which I need to fix rather quick.

I use a Dell Latitude laptop with an RS232-MPI PC Adapter to communicate with a S7-300 PLC. I can set up communication and do transfers and block compares but every now and then my connection gets aborted. This happens the most while monitoring blocks online or using a VAT.

If the connection gets lost whilst using a VAT I get a message with a text similar to "No Communication" and "Compiler info: No Handle". (I don't know the exact messages; no time to write them down)

If the connection gets lost whilst monitoring blocks I get a message "Connection Aborted".

I use a clean installation of Windows XP SP2 (Installed 2 weels ago) and Step7 Professional 2006 V5.4

I sincerly hope somebody can help me out cause I need to get this machine debugged real fast! (Tomorrow just 5 hours left)

Sounds like you have a very uptodate version of STEP7.

The problem can be some arcane software problem on the PC. Very hard to locate.
Or the MPI adapter may be defective.

1. Try to install STEP7 on another PC. PCs are plentiful, and it will tell you if the problem is with the PC or the software on the PC.

2. If the problem persists on the other PC, then ditch the old MPI adapter and get a new one asap. The serial MPI adapter is awful anyway, so just be happy that you have the opportunity to get something better.
Go for a USB MPI adapter, or the CP5512.
If you are in real trouble, call Siemens support and have them lend you one of the two.

edit:
One thing you can try is to turn down the speed from the PC to the adapter from 38400 bps to 19200 bps.
Obviously this is only possible if the adapter can switch between these two speeds. The earliest version of the adapter only had 19200 bps.

Thanks for the quick reply. I will try another PC in the future, but for now I'm stuck with this laptop. The machine is already delivered to the customer. So I'm hoping somebody has had the same problems and a ready to use answer.

I tried to slow down communication to 19.2 kbps but that was no solution.

I grabbed another RS-232 adapter at work. This one got a V5.1 mark so I hope this solves the problem. If not I can rely on the PIII-500 Power PG I also took as a backup. But I'm still hoping there is a solution to the problem.

I'll sure dump the serial adapter a.s.a.p! These things are just too slow!. I was thinking about this:

Deltalogic Accon NetLink USB

Looks promising! 12 MBPS Profibus and USB (for flexibility)

I dont know about Deltalogic, but I guess it cant be half bad.
I use a CP5511 card (but only if I dont have ethernet).
Some other guys in my company uses the Siemens USB adapter and they seem satisfied with it.

Hi,
If you decide on a Netlink and need to plug in via a piggy back connector to MPI ie (HMI fitted), You may need the Pro version.

a colleague of mine uses a systeme helmholz netlink pro but it needs a external 24v supply if not directly connected into the PLC MPI port directly.

I use either a CP5512 or a IBH Netlink which doesnt need external 24v

Hope this helps

STL

Links:

http://www.ibhsoftec-sps.de/

http://www.helmholz.de/

Jesper. Your assumption was right. My adapter was the problem. With the newer adapter no more problems! Lucky me. There was a tiny timeslot to fix the problems!

Thanks for the help.

STL???
Why would I need the PRO version. It's very likely I need to piggyback but in the specifications I find no information that would lead tho the conclusion that the PRO can do anything the USB version can't, except more connections and DHCP support. Could you please elaborate because I want to make the right choice.

Hi Bakkei.

The ethernet adapter from Helmholz or others may be a good alternative.

But I like to have the possibility of going online directly via Profibus. I do a lot of Profibus i/o so it is important to me (*).
If you dont do Profibus, then dont worry about this.

edit *:
What is important is that my CP5511 can do some diagnostics on Profibus that a USB adapter or Ethernet adapter cannot.

Looking over the specification the USB version looks ok, The deltalogic version is identical in both apperance + specification to the helmholz adaptor. When i was looking for my Netlink,the USB version was similar to the Lite version, hence no external power option ~ looks like things have moved on a bit.

The IBH Link i use doesnt need external 24v power, If you connect to alot of PLC's like me then connecting up 24v is a pain.

Regards
STL

hi !


i have a similar (not same) problem when i was trying downloading the blocks to S7 315-2DP CPU & S7 400h SYSTEM CPU (i do not remember the cpu type). The laptop hanged.

i am writing it done. may be it would help and give some additional info.

When i was downloading to s7 315-2dp cpu, i thought some problem in WIN-XP. So i rebooted the computer and repeat. but same problem again hanged up. finally i succeded when i downloaded one block at a time.

Same thing happens when i was downloading blocks to cpu 400H system cpu. That time i was having CP card. so i downloaded through PCMCI slot of LAPTOP and succeeded.

sanjay