FP-2000 clock is 15 minutes slow per day

[gerwim]

My FP-2000 system clock is about 15 minutes slow per day. How come?

Is it possible to adjust it?

Because it is running stand-alone it cannot be adjusted remotely. It is only connected to a PC every once in a while.

Regards,

Gerwim

[RikPrins]

Hello Gerwim,

The clock on the FP-2000 has normaly an accuracy of about +/- 1min/Month. However the process on the controller that is running the clock is a low priority process. When you controller has higher priority tasks to perform, which take a lot of processing power, it can happen that the clock will get behind more then usual. When a host computer is connected to the system the controller will check with the host computer (its time server) if the clock is running correctly and adjust it when needed. At Stand-Alone Base this timeserver is not available.

There is a VI under: Real-Time>>RT Utilities which is called RT Set Date and Time which can be used to set the date and time on the controller. The problem is however that you would need a reference to set your clock to. If the amount of time the clock runs behind every day is pretty consistend maybe you can use this VI to adjust the clock with a certain amount of minutes every now and then. Ofcourse you still will not have a very accurate clock setting but still more accurate as it was. The only other option you would have is a permanent time-server connected to the FP controller. 

Hope this helps,

Regards,

RikP - National Instruments Applications Engineering

[Matthew_Williams]

When you say the 'system clock', are you referring to one of the OS sourced times like 'Get Date/Time in Seconds',
or are you referring to a hardware souced time via an FP Read timestamp?

My understanding is that the OS sourced times will be slowed during periods of high CPU usage, just like in a PC.
The FP Read timestamps get the time from the hardware clock, which should not lose time to high CPU usage.

We update a LV2 global with an FP Read timestamp every time we do a read and then use that global as our
time reference in other locations.

Matt

[gerwim]

I already use the RT Set Date & Time utility every time the host PC contacts the FP-2000. But there may be a week or more between those contacts.

Thanks for the advise anyway.

Gerwim