Siemens Micromaster F070 Profibus Fault

Today I discovered something that has eluded me for the last few years, and now when I look at the manual it all becomes plainly obvious. Anyone who has programmed the control for a Siemens MM420/440 on S7 over profibus will no doubt have had the misfortune to come across the "F070" fault.

Reading the manual about this fault you get the following explanation

Having spoken to siemens tech support, I am told to check cables, terminations and other physical components.

Anyhow eventually some guy in a factory on a night shift tells a friend of mine that F70 is caused by having the "Enable Setpoint" and "Setpoint Valid" outputs off. I make a change to a bit of test code that switches these two bits on all the time and voila, problem solved.

I wonder why Siemens tech support didn't tell me to check this first.

Control Notes Blog - Foreward

I work as a controls engineer for a UK company. We use many different bits of control equipment and I can never remember the various things I have learned at great pains or I cannot find the piece of paper because its been 1) thrown away 2) 6S'd away 3) I have lost it or whatever. Anyhow this is going to be my note book for all that kinda crap until I get bored or forget the password or address or whatever.