I recently collected a large amount of data from an application in which the DT800 did not have continuous input power. I had the program set as the RESET job so that if the internal battery died, it would start collecting data again as soon as power was reapplied.

The logging worked perfectly, however (there is always a however!), when uploading the data the logger had a problem at the breaks in time for schedule A only.

The indications were as follows when attempting to unload schedule A:

1. The data input activity indicator on the computer would stop flashing after some amount of time
2. The data hub indicator also stopped flashing
3. The card busy indicator on the DT800 stopped blinking a few seconds after the others stopped flashing
4. No messages appeared in the event log stating anything was happening
5. Quitting the unload or any other attempt to gain status had no effect.

The only alternative at this point was to disconnect from the DT800. When I did this, all of the indicators above began flashing again and the unit disconnected.

When I reconnected, the ulast would be updated to the last amount of data downloaded and I started a new download (to a new file) from that point.

I had to do this 23 times for schedule A of my program. In each of the created files for schedule A there was one data point of the schedule B data just before the program stopped unloading. When unloading schedule B,C, and D I could unload the whole dataset.

I am using SW version 800 3 16 0001.

Good morning Tohag,

What was the state of the battery charge?
Were you connected to mains or an external battery at the time?
I'm wondering if the logger had enough power to work correctly

Regards,
Roger

Initially the internal battery was fully charged, but this application involved a battery powered vehicle where power was supplied by the main vehicle battery (through a DCDC Converter stepped down to 15VDC).

When the vehicle was keyed off, the DC DC converter had no power. I knew that the DT800's battery would run out of juice but I had to collect data (as much as possible) with the vehicle off as well as with the vehicle on.

So I made the job the RESET job so that after the DT800 battery died and the vehicle was keyed back on (external power was reapplied) the DT800 would start up and begin logging data again. This method worked perfectly except the phenomenon I described previously.

My job included 4 schedules (A,B,C and D). When uploading B,C, or D, the whole schedule was uploaded -- no problem. When uploading schedule A or uploading all schedules together, the previous problem occurred.

I realize this application is probably outside functional design requirements of the unit. It performed very well considering. I just wanted to make you aware of what I observed. Field testing is the best development tool if you ask me!

I forgot to mention that when I uploaded the data, I was connected to building power through the adapter (back at the office). The DT800 was no longer in the test environment.

Good morning Tohag,

There is another approach that works better. What we have done in the past is to set the dataTaker for sleep mode. Now with RS232 communications if you apply 12VDC to the CT pin the RS232 device will wake up.

The Serial Sensor port on the DT800 has CT pin. What you do is make a little timing circuit that applies 12VDC to the CT pin several second after the power is applied. This is to ensure you have a good clean signal to wake the DT800 because during the start up process on a car the voltage can drop quite low while the engine cranks over. The delay is to over come this.

The other thing you need to do is connect this signal to a digital input. Use this digital input to turn on and off sleep mode and schedules as required.

Regards,
Roger

I tried sending an e-mail and got a message that said the recipients e-mail address was not valid. I am interested in your example code. I am new to DataTaker and am not familiar with the code. When I see it I can interpret it but as far as writing it I have no experience. My e-mail address is in my profile. Thanks

Tom Haggerty

Good afternoon Tom,

I'm finally getting around to posting some code for you. This is written for DeTransfer. There is a bug in the current firmware which has been corrected with the current beta (3.99.0007) so if you want to try the code you may need to load up the beta firmware, but please remember it is under test.

The DT800 will wake up when 12 VDC is applied to the CT pin on the RS232 interface. There is a CT connection on the Serial Channel which in nice an easy to access. The second thing is we then check to see if the voltage is high or low and start or stop the schedules as required.

To wire it up connect your 12 VDC power to the terminal block.Take a wire from the 12 VDC supply and wire it into the CT on the "Serial Channel" and to digital input 1.

When the power is turned on, power is supplied to the CT pin waking the logger and to Digital input 1 which has an alarm which starts and stops other channels as required. Power on start other schedules running. Power off Stop all other schedules. DO NOT turn off schedule A or the logger will not wake up when required.

BEGIN"WakeUp"
P15=1
RA"Sched _A"1E LOGONA GA ' Trigger schedule A on the rising or
' falling edge of digital input 1
1DS ' Log the digital state (If you want)
ALARM(1DS>0.5){[GB /K]} ' If digital input 1 is high Start other
' schedules running and turn on house
' keeping.

ALARM1(1DS<0.5){[HB /k]} ' If digital input 1 is low Stop the
' other schedules from running and turn
' off house keeping.

RB"Do Stuff"1S LOGONB HB ' Here's where the work is done.
1V
2V
LOGON
END

Regards.
Roger