Communication Problem, Siemens 115U 944B


Thread Starter

B.Van den Berghe

I have a siemens 115u 944B plc. When trying to go online it gives me an error. Trying a different cable or another processor, the problem stays the same. Trying to go online with the same cable and pg with an siemens 95U is not a problem.

Software version STEP 5 V7.1

Is there anybody who can help me ?

Hakan Ozevin

If you were using a PC, I would say that might be your STEP 5 version is for "kleinsteurungen" i.e. 90/95/100 U, but if you are using a PG, this cannot be the problem.
Are you using a PG 720 and working with the battery, that is, not connected to the mains with the adapter? Some CPU's cannot be online in battery operation.

Try to check Siemens online customer support as well.

Good luck

Hakan Ozevin

Ing. Rodolfo Dotro

Are you sure that the port used is right. Because the 944B have two ports, but only one is the PG port. Is the more deep
Some other possible reasons for your problem are...

1. There is a known fault with the com ports when Step5 ver 7.1 is run under Win 98.

2. There is a problem with the 944 Processor when the second interface is occuppied!.

Try removing what ever is connect to the second interface and try your PG connection again.

Siemens now have a very good online help section....

Luc Haverhals

Be sure to use programming port S1 if you have two ports on your CPU. Ports S1 and S2 are not identical.

Luc Haverhals