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.

Siemens S5 Overall Reset (OR)

I had the great misfortune this week of being called to look at a machine with a Siemens S5 115 CPU in it.

• The stop lamp on the CPU was flashing.
• The BASP lamp on the CPU was on.
• The CPU would not go into run mode.
• Looking at the status stuff online in S6, the NINEU flag was on.

Upon reading the manual it became obvious a CPU Overall Reset would be required. The NINEU flag being on means a cold restart is not possible. It being over 10 years since I last worked on a S5 I was unsure on what would happen when I performed one. To be safe, I uploaded all program, organisation and other blocks onto a laptop using S6, because the RAM is totally wiped by the OR. Luckilly the CPU had an EPROM with all the program blocks and stuff so there was no need to download the project after the OR.

Siemens Manual Snippet OR using Switches on CPU

If you cannot be arsed to read the above snippet then do the following.

1. Put CPU run/stop switch into STOP
2. Hold OR switch in OR position
3. Toggle run/stop switch into run position two times. So stop-run-stop-run-stop
4. Release the OR switch
5. Download program (if no EPROM fitted)
6. Put run/stop switch into run

Anyhow, the OR was performed as shown, the CPU was switched back into run and everything was OK. I compared the online and offline programs.... identical. Sweet.