Can anyone tell me how on earth you change the time on a siemens vdo digi tachograph please?
A complete idiots guide would be handy !!
You don’t. Digital tachos stay at the same time regardless of time changes here.
You don’t need to, it should change automatically provided you don’t have a blanking card or a tachograph card in the second driver position (which you don’t need to have on these tachos).
EDIT Ooops, wrong tacho 
I understand that they stay on GMT time permannently, but the display hasnt changed over to in my case CET or 2hrs in front of GMT.
Is it possible to change it, and also if you get stopped by the police do they care what time the display shows?
I would have thought that the time had to be correct for recording on any type of tacho.
Let’s just use the scenario of you getting into trouble with the law,and they say,‘At xyz time you were doing this.’ That being the case,you could say, ‘At xyz time I was elsewhere.’
I’m sure that there is only a tiny tolearnce on time recording instruments in vehicles,say 5 minutes,and any other would be constituted as an offence.
In the case of digi tachs,isn’t this a serious oversight?
Ken.
Hombre:
If you get stopped by the police do they care what time the display shows?
I wouldn’t think so, as long as the main internal clock is correctly set to GMT then all the recording stuff and the data on your card will be correct.
Is there not a manual for the tacho in your truck? If not then ask your employer as they should have one that came with it when it was new.
Paul
You don’t have to change it as they are set on utc time but if you need to all you do is get into main menu and then time and change it from there it’s quite easy when you done it a couple of times. The hard part is getting into the main menu without getting half a dozen print outs.good luck 
Hombre:
Can anyone tell me how on earth you change the time on a siemens vdo digi tachograph please?A complete idiots guide would be handy !!
Ask and you will receive.
You can change the local time which will change the time displayed, this doesn’t effect the UTC time.
I’m not sure about this but I’m sure I’ve read somewhere that you should not try changing the time on a Siemens tachograph with the driver card in.
Guides to changing the local time on digital tachographs.
Quinny:
I would have thought that the time had to be correct for recording on any type of tacho.Let’s just use the scenario of you getting into trouble with the law,and they say,‘At xyz time you were doing this.’ That being the case,you could say, ‘At xyz time I was elsewhere.’
Not really. If the incident happened at 14:00 BST today and you produced your data from your digi card, either by download or printout, you would use whatever you were doing at 13:00 UTC to prove your case. It is not as if you could have altered the time to cover something up as the you can only alter the set time on a digi tacho by 1 minute per week.
Quinny:
I’m sure that there is only a tiny tolearnce on time recording instruments in vehicles,say 5 minutes,and any other would be constituted as an offence.In the case of digi tachs,isn’t this a serious oversight?
All the regulations regarding digital tachos are written into law and part of that is the fact they record all events in UTC, so it isn’t a problem. There would only be an offence if the UTC time was set incorrectly, and that would have to have been done by a workshop as the driver has no means of doing it.
Hombre:
I understand that they stay on GMT time permannently, but the display hasnt changed over to in my case CET or 2hrs in front of GMT.
Press OK to enter the menu.
Press the down arrow 5 times
Press OK
Press the down arrow twice
Press OK
Press up arrow twice to move displayed time forward by 1 hour
Press OK
Press back arrow about 7 times until you are back at the default screen
Job done.
Hombre:
if you get stopped by the police do they care what time the display shows?
Nope as it has no bearing on the data being recorded.
Ah, Digital Tachos, my pet subject 
The time displayed on the Vehicle Unit (VU) may have no bearing on what is being recorded by the internal mass memory and onto the driver card.
All digital tachos use UTC (Universal Time coordinated) the display can be set to show UTC or a local time (in half hour blocks away from UTC). Because the local time you enter is a number of hours plus or minus from UTC, then the local time displayed will never alter automatically as UTC is constant. To change local time you will have to follow the procedures outlined above. Personally I wish the local time thing had never been done. It causes no end of confusion especially if you have to put manual entries in, they have to be done in UTC and NOT local time.
Only the very stupid enforcers will worry about what time the VU is displaying. The cleverer ones know that it is UTC that is important and know how to get it displayed / printed. If the VU is more than 20 minutes adrift from real UTC expect to be visiting a tacho workshop in the very near future.
If proceedings are taken against a driver then the Scn 9 Statement (in the UK) is worded to explain the difference between UTC and local time.