Siglent SDL1000X/SDL1000X-E Electronic Load

[Martin72]

I actually have everything together for the tests.
I also bought the small black power supply unit to have more than 3A available (10A).
Then an LED driver from meanwell with 1050mA constant current.
With the other power supplies I can test the maximum power, e.g. the 2x60V to 120V and 3 A are 360W.
Plus my Tektronix current clamp and a small siglent scope.
So it will start soon.
One thing I tried out earlier was the meanwell led driver.
You can actually see a significant ripple on the current.
More on this at the weekend.

[ddrl46]

Has anyone been successful in performing an adjustment on this unit? The procedure in the service manual is a bit confusing...

[SHF]

Hmm black power supply not nice   

[Martin72]

OK,
Then I already have a black one.

The procedure in the service manual is a bit confusing...

That's why Siglent withdrew it again, there were too many requests regarding the calibration.
However, it must also be said that calibration is only due when the load has run out of its specification.
This in turn can be tested and/or the "Verification Performance Test" from the service manual can be carried out.

[theblinkingman]

Can somebody please post the service manual with the calibration procedure again?

[theblinkingman]

I messed around a little bit with calibration and generally it seems to work like described.  The adjustment is a little bit coarse, so I didn't get it dialed all the way in. 

It's not mentioned in the manual, but you can save off the current calibration by running CAL:MEAS? and CAL:CTRL?. It returns something like 0.000668,1285,0.002859,1292,0.000084,884,0.000502,797 which are the "a" and "b" values you set with CAL:DATA <1 or 2>,"a","b".  1 is for the CTRL calibration and 2 is for the MEAS calibration.  The first two numbers are for the 36V CV range and the second two are for the 150V CV range.  I believe the last two a/b pairs are for CC mode for both ranges too.   

When setting the calibration, it applies to the voltage range that is currently active and currently active mode (CC or CV). 

Remember to CALCLS:VOLT before starting (and after you've saved your existing calibration).  CAL:ST stores and applies the calibration values.  The load doesn't like it when changing the CTRL values while it is enabled. 

Here's a quick script for calculating the a and b values for CV, but I found that I had to play around with the numbers afterwards to get a decent result. 

Code: [Select]

#!/usr/bin/env python3

# Voltage calibration in CV mode
# *_dmm is the voltage measurement done via external meter
# *_sdl is the voltage measurement displayed on the load
# y1 is CV at 1V and y2 is CV at 10V.  Set the power supply ~15V CC .1A
def calc(v_range, y1_dmm, y1_sdl, y2_dmm, y2_sdl):
    # start with voltage limit set to 1
    v_set = 1
    ctrl_const = 2000 if v_range == 36 else 1500
    # v_range = 36
    # v_range = 150

    ctrl_x1 = (65536 * v_set) / v_range
    meas_x1 = (65536 * y1_sdl) / v_range

    # next set voltage limit to 10
    v_set = 10
    ctrl_x2 = (65536 * v_set) / v_range
    meas_x2 = (65536 * y2_sdl) / v_range # Not used?

    ctrl_step = (y2_dmm - y1_dmm)/ (ctrl_x2 - ctrl_x1)
    ctrl_offset = ctrl_x1 - (y1_dmm / ctrl_step) + ctrl_const
    meas_step = (y2_dmm - y1_dmm) / (ctrl_x2 - ctrl_x1)
    meas_offset = meas_x1 - y1_dmm / meas_step

    print(f"CAL:DATA 1,{ctrl_step:.6f},{ctrl_offset:.0f}")
    print(f"CAL:DATA 2,{meas_step:.6f},{meas_offset:.0f}")


# First start with the 36V range
calc(36, 1.5111, 1.9507, 12.445, 10.934)
# Switch into 150V range and do it again (values should be different)
# calc(150, 1.5111, 1.9507, 12.445, 10.934)


[Mortymore]

My 6 month old Load is starting to look like this one.
Is this a known display problem?

After a month out for Siglent repair services, my SDL returned yesterday and under warranty the LCD and mainboard were replaced. New HW version 03-03-022
Welectron took care of all the shipping process through UPS.