I'm trying to chain measurements between different instruments. the last part of this chain is made by a SDM3055 and a SDM3065 to measure respectively current and voltage.
Here I'm only concerned with timings, I setup a burst of pulses that I fed into the 3055 trigger input, its VMC out is then fed into the trigger input of the 3065X all 3 signals (including VMC out of the 3065) are recorded by the scope.
In the manuals VMC OUT is described to go off AFTER the measure has been completed. My experience is that it goes off after some preliminary stuff and BEFORE the actual measurement (aperture) happens
how can I say so? by looking at scope traces it is quite easy to deduce it. Moreover the position of the VMC out signals does not depend on aperture duration.
the two instruments have been set up by software and the parameters on the display correspond to the programmed setting. Here it is the relevant part of the setup
class Voltmeter(SDM):
def __init__(self, **kwargs):
super().__init__('192.168.1.9', **kwargs)
def setup(self, n=10, nplc=0.5, delay=0.0):
self.write(':*RST')
self.write(':CONF:VOLT:DC')
self.write(':VOLT:DC:RANG 20')
self.write(f':VOLT:DC:NPLC {nplc}')
self.write(f':TRIG:COUN {n}')
self.write(f':TRIG:DEL {delay}')
self.write(':OUTP:TRIG:SLOP POS')
self.write(':TRIG:SOUR EXT')
self.write(':TRIG:SLOP POS')
self.write(':SENS:VOLT:DC:AZ OFF')
self.write(':SENS:VOLT:DC:NULL OFF')
def init(self):
self.write(':INIT')
class Ammeter(SDM):
def __init__(self, **kwargs):
super().__init__('192.168.1.5', **kwargs)
def setup(self, n=10, nplc=0.3, delay=0.0):
self.write(':*RST')
self.write(':CONF:CURR:DC')
self.write(':CURR:DC:RANG 200mA')
self.write(f':CURR:DC:NPLC {nplc}')
self.write(f':TRIG:COUN {n}')
self.write(f':TRIG:DEL {delay}')
self.write(':OUTP:TRIG:SLOP POS')
self.write(':TRIG:SOUR EXT')
self.write(':TRIG:SLOP POS')
def init(self):
self.write(':INIT')
voltmeter = Voltmeter()
voltmeter.write('*RST')
voltmeter.setup(nplc=10)
ammeter = Ammeter()
ammeter.write('*RST')
ammeter.setup(nplc=10)
voltmeter.init()
ammeter.init()
scope.single()
trigger.start()
Has anyone been successful in getting VMC out signal AFTER the aperture time?