i think i know the problem.
my pc clock does sometimes change a second faster than a second should last... so it sometimes goes quiker to the next second. i dont know how to solve this. it is synchronized to a internet clock but that doesnt synchronize every second...
If you are using the automatic clock synchronisation option do not set the "Allowed clock deviation" too tight, e.g. 1 s as you will end up with the PC trying to change the clock every time either due to drift in its own clock or because of delays in the communications from PC to logger (although we do try to compensate for this). If the clock is updated too often you can risk the logger "skipping records", i.e. storing data, if the time is pushed for just before it is supposed to store data.
A word of warning - whilst most PCs are synchronised to internet time usually the default update time is several days and a PC can typically drift tens of seconds in that period.
When i set Allowed clock deviation to 2sec. then i get error like below:
(i dont even understand the public clone either, whats that clone about?)
Loggernet TroubleShooter Network Analysis
7-2-2011 17:47:09
COM4: ComPort
Communication State is normal.
The COM Port connection is Prolific USB-to-Serial Comm Port (COM4).
PakBusPort: PakBusPort
Communication State is normal.
The Max Baud Rate is 9600. If directly connected to the computer, the baud rate may be increased to 115200.
CR1000: CR1000
Communication State is normal.
The PakBus Address is 1.
Scheduled to collect at 7-2-2011 17:46:55
Collection intervals passed with no data collected: 967
It has been 0d 0h 16m 7s since data has been collected.
Recent Communication Errors
Warn CR1000: 7-2-2011 17:46:25 | "transaction failure","timed out or resource error","table poll - Public_Clone"
Warn CR1000: 7-2-2011 17:46:36 | "transaction failure","timed out or resource error","check/set clock"
Warn CR1000: 7-2-2011 17:46:44 | "transaction failure","timed out or resource error","table poll - Public_Clone"
Warn CR1000: 7-2-2011 17:46:55 | "transaction failure","timed out or resource error","check/set clock"
This indicates there is a basic communication problem between the datalogger and PC. You would get similar messages if the logger was not plugged in or powered off.
I would start by checking where the cables are plugged in, power supplies etc.
ive checked the connections and the only fault i could see was a resistance shunt touching another one.
Allowed clock deviation is now set to 2 sec.
Almost every minute my clocks differ and are till now adjusted by the automated clock check. i hope it will continue to work like this and that the clocks doesnt differ for more then 10 sec. as before...
Please remember the spec of the datalogger clock. At worse it will drift about 0.5 sec per day. In fact the error will be much less than that over a limited temperature range.
This is an order of magnitude or better than most PC clocks unless they are being updated by a decent clock standard every few minutes.
Even with a 2 sec deviation you risk keep pulling the logger clock back and forward to a bad PC clock for no good reason.
Incidentally I recommend you check on the internet that you have the latest USB drivers for your USB serial port as some of the older Prolific ones did have problems.
ive downloaded the latest version of prolific driver but i cant get it to work, the vista one worked for me.
Are there other brands which i can have a try, are there drivers from Campbell?