Which device are you using?
I presume you are referring to the SetTrigger2 function in the block diagram.
Referring to the Programmer's Guide (http://www.picotech.com/document/pdf/ps3000pg-en-2.pdf
), section 2.4.11 ps3000_set_trigger2 shows the parameters to be passed in with a description of what they represent:
- handle, - handle to the unit
- source, - the channel - 0 is channel A
- threshold, - the threshold voltage in ADC counts
- direction, - an enumeration for whether the signal is rising (0) or falling (1)
- delay, - percentage of data points that are pre-trigger/post-trigger
- auto_trigger_ms - delay (in ms) after which the trigger will occur automatically
You will need to set the value for threshold
in 16-bit ADC Counts. You can use the following formula to do this:
adc_counts = threshold (milliVolts) * max ADC value / range
so for example, a threshold of 1000 mV and a range of +/-2000mV would result in
1000 * 32767 / 2000 = ~16384
I hope this helps - if you do require further assistance with this, please do respond to this post.