FAQs from Rohde & Schwarz

Response time of the device


We are using the HMC8012 for automatized tests. I have tried using both the fetch as well as the read commands, but the response time from the device is still about 1 second before any value is returned. Is it possible to have a faster response time than this?


The measurement rate depends on several factors.

1.) There are three different reading rates available to set the instrument to:

  • Slow = max. 5 readings / sec.
  • Medium = max. 10 readings / sec.
  • Fast = max. 200 readings / sec.

2.) It takes some additional times to switch either the measurement range or function and get the first valid ADC reading.

Always keep in mind to avoid auto ranging for maximum sampling speed. Changing between for example Voltage and Current will take some additional time.

3.) The way how the measurement values are gathered:

One way is to get the values with typical SCPI commands followed by reading the returned buffer information.

This will lead to an answer after a medium response time of about 28 to 30 ms.

The values sometimes repeat for three or more times due to the resolution of the ADC.

Another (much faster) way is to use the undocumented command "DATA:STREAM 1" which is explained in the FAQ article "HMC8012: Measurement of data stream".

Tested with:
HMC8012 V1.400