I am looking for a programmable power supply that has very high resolution on the current readback value. Searching the internet, I found this:
https://www.salukitec.com/sps81x-series-programmable-dc-power-supply/
According to the specs, the resolution on the current reading is 0.001 mA, or 1 μA. I asked the company for a quote, and they said it's about $700. That's a lot of money, but much less than what other manufacturers would ask for a programmable PSU with the same current readback resolution.
Is this legit? Any thoughts on the SPS831 unit or the Saluki company in general?
https://www.salukitec.com/sps81x-series-programmable-dc-power-supply/
According to the specs, the resolution on the current reading is 0.001 mA, or 1 μA. I asked the company for a quote, and they said it's about $700. That's a lot of money, but much less than what other manufacturers would ask for a programmable PSU with the same current readback resolution.
Is this legit? Any thoughts on the SPS831 unit or the Saluki company in general?
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0.001mA is more like 1μA than 1nA 😉 , and you're probably looking for a ''high resolution'' really.
Oups, my bad. Thanks for pointing this out. I fixed my post accordingly.
Any thoughts on Saluki / the SPS831 unit?
Any thoughts on Saluki / the SPS831 unit?
Never heard of them before. Try to find some reviews and teardowns to see if it's built just like any other cheap run-off-the-mill chinese equipment.
The brymen 869s has a 500K count mode for DC and gets down to 0.00001V (0.01mV) resolution and uA modes. So the question i have would be what’s the variation over time/temp? Can you set voltage/current to that that resolution?
Does it use force&sense with a guard (i’d assume so).. etc.
Does it use force&sense with a guard (i’d assume so).. etc.
The resolution of the set value does not need to be as good as on the readback for mg application.
What do you mean by force&sense with guard?
The Brymen 869s is a DVM, but I need a programmable power supply.
What do you mean by force&sense with guard?
The Brymen 869s is a DVM, but I need a programmable power supply.
Agreed that it’s a 5.5 digit DMM but my points stand.
4 lead means the PSU is sensing the power at the end point and not at the output of the power supply. A guard helps reduce the noise thus the digits bouncing.
It’s not clear on the stability over time or temp in terms of accuracy and precision. Also this is 5.5 digit.. +/-4.9999V I assume but the PS states 0.001mA. The specs just seem confusing.
4 lead means the PSU is sensing the power at the end point and not at the output of the power supply. A guard helps reduce the noise thus the digits bouncing.
It’s not clear on the stability over time or temp in terms of accuracy and precision. Also this is 5.5 digit.. +/-4.9999V I assume but the PS states 0.001mA. The specs just seem confusing.
You need only the reading resolution or also precision in setting and maintaining this at the output?
I am thinking of using this for testing of low-power transistors: set the voltage to a predefined value, then read the current.
I only need the reading resolution via the the computer interface. I don't care much about the display on the front panel.
I only need the reading resolution via the the computer interface. I don't care much about the display on the front panel.
I guess these are the noise/ripple specs at max. power. At lower output, the noise/ripple will likely be (much) less. Also, the readback values are most likely some sort of an average value integrated over many cycles of the ripple signal. This means the readback resolution value may indeed be much smaller than the ripple/noise spec.
I could not resist and ordered an SPS831 from Saluki. They were were easy to deal with, and the SPS831 seems to do what it says in the datasheet.
At the beginning, the current readback values were about 0.3 mA lower than the true current (I determined this using a high-ohm resistor and measured the voltage drop using a DVM). While this was well within the specified accuracy, this offset was a bit inconvenient, especially because the current was reported as zero once the true current was less than 0.3 mA. I asked the support at Saluki, and two days later they sent a firmware upgrade that does an auto-zero, which eliminated the problem. I can now measure with the full 1μA resolution down to zero!
The Saluki devices are also available from other companies/brands (Maynuo, Hopetech/Hopeinstrument, maybe others). Not sure which is the original manufacturer.
At the beginning, the current readback values were about 0.3 mA lower than the true current (I determined this using a high-ohm resistor and measured the voltage drop using a DVM). While this was well within the specified accuracy, this offset was a bit inconvenient, especially because the current was reported as zero once the true current was less than 0.3 mA. I asked the support at Saluki, and two days later they sent a firmware upgrade that does an auto-zero, which eliminated the problem. I can now measure with the full 1μA resolution down to zero!
The Saluki devices are also available from other companies/brands (Maynuo, Hopetech/Hopeinstrument, maybe others). Not sure which is the original manufacturer.
The Saluki looks like a pretty peremium product. I could not find any pricing. If it were from a major TMI company it would be at least $1,300 or more. The Keithley Source Measure boxes seem to start at $5k. Taiwan is a good place for specialty manufacturing. China won't answer the phone for small quantity premium stuff but Taiwan is well set up for that. And better quality usually.
I payed $649 for the Saluki. I also bought their USB/Serial-TTY converter cable ($36) for peace of mind, but I believe I could have saved a few coins by using a standard FTDI cable instead. Saluki were were nice to deal with, and they provided fast and very useful feedback to my questions. Much better than Keithley, who sold me their 2280S for more than 3x the price of the Saluki, but were not able to provide a working example of the SCPI commands needed for the 2280S to set a voltage and current limit, and then read the voltage and current values. Had to return the Keithley 2280S due to poor support...
I like what I see here and here.