PCSU 200 continuous mode and square wave stability

Hi,
I’m using the PCSU 200 from a collegue, which is out of office. I’m struggling with two problems.

  1. I’d like the oscilloscope present the signal in a continuous mode. But as far as I can see, there’s only intermitted signal achievement possible with the supplied software “PCLab200”. Is this right?
  2. After connecting the output of the signal generator directly with the input of channel 1 I switched the generator to square wave output form. When changing the duty cycle the whole signal shifts up (for low duty cycle) or down (for high duty cycle). The only thing stable is the DC,rms value of the signal with about 0.34 V (according to the PCLab). I’d like to have the low and the high voltage of the square wave as stable values, independently from the duty cycle (like always ±1 V). Is this possible?

Thanks a lot for your advises.

[quote]1. I’d like the oscilloscope present the signal in a continuous mode. But as far as I can see, there’s only intermitted signal achievement possible with the supplied software “PCLab200”. Is this right?[/quote]Yes, in the oscilloscope mode the acquired data is intermitted.
In the Transient Recorder mode it is possible to record continuous data but only very low frequency.

[quote]2. After connecting the output of the signal generator directly with the input of channel 1 I switched the generator to square wave output form. When changing the duty cycle the whole signal shifts up (for low duty cycle) or down (for high duty cycle). The only thing stable is the DC,rms value of the signal with about 0.34 V (according to the PCLab). I’d like to have the low and the high voltage of the square wave as stable values, independently from the duty cycle (like always ±1 V). Is this possible?[/quote] I’m sorry this is not possible with the PCSU200. The function generator output is “AC coupled” and the average output DC value is always about zero.
The PCSGU250 and PCGU1000 can output DC biased output waveforms.

To 1.
This is in fact an interesting option.

To 2.
Good to know, that the generator is working in spec. I’ll use a workaround.

Thanks anyway for the very quick answer.

Is the square wave output from the PSCU200 function generator usable for calibration purposes? Most stand-alone bench oscilloscopes have an output which spits out a 1kHz square wave at a volt or so for test purposes, to verify that x10 probes are adjusted properly to display a square-wave input signal that’s actually square (and not distorted by stray capacitance). What I’m seeing if I have the PSCU200 display its own function generator output as an oscilloscope trace isn’t quite square at any frequency, as if the high-frequency components of the signal were being attenuated.

I’m also unsure about how the oscilloscope trigger works on this unit. A stand-alone oscilloscope allows the trigger to be set to a specific voltage (which is displayed both as a number and as an arrow beside the traces at the screen edge) and allows selection of ‘auto’ (which keeps triggering in a free-running manner if the incoming trigger signal goes away) and ‘norm’ (which on a digital scope freezes the last valid triggered input on the screen until the signal becomes active again), as well as any one-shot or storage modes. Is there an ‘auto’ trigger mode on the PSCU200?

[quote]What I’m seeing if I have the PSCU200 display its own function generator output as an oscilloscope trace isn’t quite square at any frequency, as if the high-frequency components of the signal were being attenuated.[/quote]Can you please post a link to the captured waveform image (File -> Save Image) so we can check if your unit is working OK. The waveform should be quite square.

[quote]Is there an ‘auto’ trigger mode on the PSCU200?[/quote]I’m sorry, there is no auto trigger option. Only trigger ON and trigger OFF are the options.

This is what I get when I save the raw data (after omitting duplicate measurement points). When the signal goes high, the raw measured value jumps to 169 then gradually crawls up to 173:

I’m using a PCSU200 and a pair of PROBE60S. All are new. I’ve tried using the yellow plastic adjustment screw on the x10 probes but at every other setting the signal looks worse (slower rise time, less amplitude).

[quote]When the signal goes high, the raw measured value jumps to 169 then gradually crawls up to 173[/quote] This looks OK.

[quote]I’m using a PCSU200 and a pair of PROBE60S. All are new. I’ve tried using the yellow plastic adjustment screw on the x10 probes but at every other setting the signal looks worse (slower rise time, less amplitude).[/quote]Please try to do the adjustment at 1kHz (or 500Hz) to get better response.