EEVblog Electronics Community Forum
Products => Test Equipment => Topic started by: EEmuse on December 11, 2018, 01:51:45 am
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Just got a Siglent SPD3303X-E power supply. With the current limit set to 0.00A, CH1 is in CV mode and outputs voltages up to its max rating of 32V. It seems that it outputs up to 1.5mA before going into CC mode (I calculated this value using Ohm's law: I applied a known voltage across a resistor of a known value and calculated the current). Note that CH2 behaves as I would expect: it goes into CC mode when the current limit is set to 0.00A and the output voltage stays zero. Is this acceptable?
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Welcome to the forum.
Do consider the datasheet spec of 10 mV/mA resolution and the Program Accuracy spec.
http://www.siglentamerica.com/wp-content/uploads/dlm_uploads/2017/10/SPD3303X_DataSheet_DS0503X-E01A.pdf (http://www.siglentamerica.com/wp-content/uploads/dlm_uploads/2017/10/SPD3303X_DataSheet_DS0503X-E01A.pdf)
Can I suggest you try the same check from within the EasyPower external software interface where 1 mA/mV adjustments are possible for X-E and X models.
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Welcome to the forum.
Do consider the datasheet spec of 10 mV/mA resolution and the Program Accuracy spec.
http://www.siglentamerica.com/wp-content/uploads/dlm_uploads/2017/10/SPD3303X_DataSheet_DS0503X-E01A.pdf (http://www.siglentamerica.com/wp-content/uploads/dlm_uploads/2017/10/SPD3303X_DataSheet_DS0503X-E01A.pdf)
Can I suggest you try the same check from within the EasyPower external software interface where 1 mA/mV adjustments are possible for X-E and X models.
Thank you for your reply. I tried setting the current limit to 0.000A in EasyPower, but CH1 still behaves as previously reported. Any other suggestions?
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Rather than try to calculate it, get a multimeter on the mA range on the front and see how it behaves. My SPD3303X-E (software upgraded to SPD3303X) when set to 32V and 0mA or 1mA has somewhat differing behaviors, usually charging the output gradually, but it seems there's some offset in the reading between two channels - in 1mA output mode, my channel one puts about just under 400uA, whereas channel 2 puts about 1.5mA or so when shorted. Because of the fairly week current from channel one, this causes the output to charge to a point and then partially discharge, whereas channel two charges all the way to the set 32V. Both of these measurements are within the noise floor of the instrument, and both are substantially less when set to 0mA - virtually nothing (actually reads negative) on channel one and about 430uA on channel 2.
If you can measure the behavior of the outputs as leaking that much, there is probably something wrong, but it's also probably within specification - these supplies are not designed to output tiny currents. If you need a tiny amount of current supplied to your device, I suggest using a load resistor on the output terminals to keep the current output to 10mA or more as a baseline, and of course you want to be measuring those tiny currents with a meter outside of the indicator on the front panel of the power supply, the readout is not specified to read down to those tiny output levels accurately.