Products > Test Equipment
Siglent SPD3303X-E Hi-Resolution Output Unlock?
mawyatt:
We got a few moments of "free time" and followed up with the second 3303X-E calibration. As mentioned this second 3303X-E was required to support and on-going design effort, it was "enhanced" to a 3303X following the procedures outlined here, same as was our first 3303X-E awhile back.
The 1st 3303X is used to supply critical voltages to expensive chips and has the current limits set to under 20ma, just above the normal operating currents. This has already saved the day :o A certain dumb arse we won't mention ??? used a standard Raspberry Pi breakout PCB for the 40 pin GPIO connector to get access to the 40 analog DAC channels which are on a 40 pin header and are used to drive HV amplifiers, Bi-Phase modulators and Bi-Polar offset modes in another custom PCB. When the system was turned on and commands sent via SPI to activate the various individual channels, certain channels would cause an overcurrent condition and the 3303X would go into a limit condition. This was thought to be due to shorts on the 100 pin LQFP device, after carefully viewing and probing under a microscope this was not the case, which then led to examining all the custom PCB traces for possible shorts without any discovered. So back to the setup but without the IO connector in place, no overcurrent, but with the IO connector and overcurrent condition :-// Turns out the breakout PCB doesn't route each individual pins to the male connector as expected, but ties the various common pins of the Raspberry Pi GPIO together, thus shorting certain pins as experienced |O
Anyway, the second 3303X was used for a more general supply of for VCC and VEE use and current limits set to an arbitrary 100ma and not verified. After calibration it was noted the current limit was engaged at ~80ma on both channels without any load!! This was thought to be a calibration issue and all the memory was reset and another calibration performed, the result was the same. After many memory and power resets, multiple calibration attempts, this condition still resides even tho the current readings are very accurate over the entire range, as are the voltage readings. This high OC condition seems to be an offset since the readings at actual currents also show an offset of similar value (~80ma). Both supplies exhibit very accurate voltage and current readings over the supplies full range, however only one has the correct current limit settings which are quite accurate, even at the lower ranges which was impressive performance IMO.
Both have the same firmware (1.01.01.02.05), same hardware (V3.0), same product type SPD3303X, so beginning to think this second unit has a hardware issue with the current limit circuit.
BTW I had no idea just how good this supply is regarding voltage, current and current limit accuracy (one at least), until we needed a precision voltage with low current limit and it save our butt ???
Would appreciate if a few others with these "enhanced" 3303X-E could check the current limits at lower levels like 40ma, 20ma and 10ma and report results.
Thanks in advance for any help.
Sorry for the long thread, but figured others might appreciate how this all transpired, and why a precision supply is very valuable for lab use.
Best,
Edit: Here's the setup for the project with only 4 channels, will grow to at least 64 and likely 100. Of course the multiple instances of these PCBs will be integrated into a custom PCB base, and all the Power Supplies (+-75V, +-7V, +5V, +5.5V, +6V) will be replaced with a custom PS running from a single 12V input also supporting custom computer interfaces with USB, SPI and RPi interfaces.
mawyatt:
Update, just contacted Saelig in NY where we purchased the SDP3303X-E. They have issued a RMA and sent another SPD3303X-E as a replacement :-+
Talk about value added distribution service, here is an example :clap:
Best
mawyatt:
Follow up on this. The replacement was just received and checked out, decided to "enhance" which was successful, so now a 3303X. Then a cal procedure as outlined in the service manual using a KS34465A and SDL1020X-E. The voltage and current calibrated well, but now the current limit is hosed up like the other. I know suspect something in the cal procedure we did is wrong, but been thru this multiple times and from different perspectives, same result.
Here's what's happening. After the setup and access thru VISA per manual instructions, a *IDN? is sent and everything checks out. Then a *CALCLS 8 is sent to clear all the ch1 and ch2 coefficients, then ch1 voltage calibration is followed and saved with *CALST command, then ch2 voltage, then ch1 current and finally ch2 current. The voltage outputs on Ch1 and Ch2 are spot on, as are the current readings, however the no load current limit is now ~100ma on both channels!!
Repeat the *CALCLS 8 to reset all the coefficients and noted that the no load current reading on ch1 is ~100ma and ch2 ~85ma and this is where the no load current limit trips on both channels. After a current calibration the current readings are correct but the current limit is not, it still has this ~100ma offset and still trips at ~100ma no load. So the current limit trips at the setting plus ~100ma, so for example if I set the current limit to 300ma, then the actual current of ~200ma will cause a current limit.
Then tried a *CALCLS 2 and *CALCLS 3 which clears the current settings and readings with same result as above. So it seems this is an issue in the calibration procedure with an enhanced 3303X-E.
Anyone experience this type of current limit issue?
I guess the next step is to revert back to the 3303X-E and hope this current limit issue doesn't follow.
Edit: Tried to revert back to the 3303X-E from the 3303E we now have to see if this current limit issue can be corrected. With help from tautech we were able to do this with the 3303X that has the .05 firmware version, the other 3303E has the later .07R2 firmware and the proper files back on the Siglent thread (https://www.eevblog.com/forum/testgear/siglent-ads-firmware-file-format/msg1830584/#msg1830584) only support the older .05 firmware (later files may be available tho). Eventually we were able to get back to a base line 3303X-E, however the dreaded current limit offset followed. Tried a couple CAL procedures without success, and not sure what to try next.
A possible warning to others that make the 3303X-E to X enhancement, be very careful if you decide to do a calibration. I've hosed up the current limit on two units now, and can't figure out how to correct this. Believe me we've tried at least 50 calibration attempts, cycled power 20 times, tried various ways including some on USB, others on LAN, and wasted 2 days at this. Nothing seems to dislodge this current limit offset, it even transitions firmware changes, the voltage and current readings are good tho so the supplies are not totally bricked.
One telltale symptom was when *CALCLS 8 was invoked, the no load current reading jumped up ~100ma from 0 and this became the current limit offset which doesn't get corrected when the current calibration is performed. The current limit must be set much higher than 0 even without a load and the real current limit is the setting minus this offset, so if you want 50ma, then you must set the current limit to 50ma + the offset.
Any help or insight with this issue is greatly appreciated.
Best,
blurpy:
Wow, scary. Perhaps tautech can test calibration on a stock X-E (or X) to see if it's related to the modification, or just a buggy calibration feature in general?
tautech:
--- Quote from: blurpy on July 15, 2021, 06:53:30 am ---Wow, scary. Perhaps tautech can test calibration on a stock X-E (or X) to see if it's related to the modification, or just a buggy calibration feature in general?
--- End quote ---
We have already shared many emails. ;)
All stock sold so none available to do checks on. :) :(
However after receiving a nice SPD series adjustment PDF from the factory not long ago it's already in mawyatt's inbox for when he awakes.
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