I'm attempting to use the VoltDiff instruction in a program to measure voltage across two pins. My expected voltage is between 4 and 5 volts. I've confirmed this output at the pins, and at differential channel #1 on the logger using a multi-meter. However, my program outputs outrageous values? What is going on here?
I'm using this instruction:
VoltDiff(myVariable,1,mV5000,1,0,0,250,1,0)
It outputs these values:
TimeStamp Record myVariable
2013-04-19 09:22:20.0 1467 1154502191
2013-04-19 09:22:30.0 1468 1155372626
2013-04-19 09:22:40.0 1469 1155504844
2013-04-19 09:22:50.0 1470 1155273462
2013-04-19 09:23:00.0 1471 1157657172
Thanks
Suggest you post the whole program.
Thanks for your reply. Here is the full program. I switched over to channel #2 to make sure it wasn't an issue with the channel. I'm really not interested in the magnitude of the voltage, but rather when the channel is hi and when the channel is lo. With that in mind, is there a better way to monitor a channel for hi/lo condition than what I am proposing here? I am however curious why the output of this instruction does not match the multimeter.
Public myVariable As Float
DataTable (myTable,True,10000)
Sample (1,myVariable,Float)
EndTable
BeginProg
SerialOpen (Com1,115200,0,0,10000)
Scan (1,Sec,3,0)
VoltDiff(myVariable,1,mV5000,2,0,0,250,1,0)
CallTable(myTable)
'send data to address 1
SendData (Com1,0,1,myTable)
NextScan
EndProg
Here is the data I get. The voltage should be about 5V from second 39 to second 43.
TimeStamp Record myVariable
2013-04-23 06:09:37.0 11167 -1054066827
2013-04-23 06:09:38.0 11168 -1054066827
2013-04-23 06:09:39.0 11169 1167880993
2013-04-23 06:09:40.0 11170 1167878238
2013-04-23 06:09:41.0 11171 1167875482
2013-04-23 06:09:42.0 11172 1167875482
2013-04-23 06:09:43.0 11173 1167886504
2013-04-23 06:09:44.0 11174 -1055477626
2013-04-23 06:09:45.0 11175 -1055477626
I'm a new user to datalogger CR1000 and I would like to use the differential voltage to measure voltage across three pins.
My expected voltage is between 0 and 5 volts for my 3 differents parameters : solar radiation, Cell Temps and Ambient Temp from a 5V calibrated cell.
For the moment, I can write only the programm in Short Cut without see if the programm is ok with my CR1000.
In CRBasic Editor, I have :
'Generic Differential Voltage measurements DiffVolt()
VoltDiff(DiffVolt(),3,mV5000,4,True,0,_50Hz,1,0)
Could you tell me if I use the good thing in Logernet?