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| Power Supply Series Mode for Split Dual Tracking Use |
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| mawyatt:
--- Quote from: Furna on October 10, 2024, 06:36:41 pm ---I might be lost in translation ... you want to use an SPD4000X in Series with a second PSU (no matter what brand) to create a +- supply? --- End quote --- Our use case is a single physical supply with dual (or more) independent outputs that can be configured into the "Series Mode" where 2 Channels are connected in series, like your SPD4000X and our GPP4323 and SPD3303X. In this configuration the series connection wether internal or jumper (like old HP supplies we mentioned) become the Ground and the Outputs are from one channel as +V (VCC) and other channel -V (VEE) as the 1st and 2nd channels track. Usually one expects (from experience) both channels to be same voltage magnitude and each channel should indicate the current drawn from itself. This is how the GPP4324 operates, however the SPD3303X doesn't do this as it "assumes" that CH2 is same current as CH1 and displays the current reading from CH1 into CH2 which is OK IF THE SUPPLY OPERATES IN SERIES MODE ONLY. If the supply is operating for Dual Tracking this will NOT INDICATE THE PROPER CURRENT FROM CH2!! Your SPD4000X "seems" (we don't have one so "extrapolating" based upon your comments and measurements) to operate different than SPD3303X and/or GPP4323 in that it displays the TOTAL VOLTAGE across CH2 and CH3 as the voltage on CH2 which is easily confusing (old experience), the others display each channel with it's appropriate supplied voltage accoss each terminal set (+-) as one might expect the voltage displayed on each channel as the ACTUAL VOLTAGE OUTPUT on said channel, thus CH2 displays channel 2 voltage and CH3 displays channel 3 voltage. Even if operating the SPD4000X in Series Mode only if CH3 displays any voltage this leads to potential user mistake as one might assume the total output from CH2 + Terminal to CH3 - terminal as the sum of voltage displayed as CH2 Voltage and CH3 Voltage, which would be 1.5 times the actual voltage output across these said terminals. Anyway, this is the best we can describe this condition, and from our old school perspective something that is not as expected behavior. BTW the USE of capitalization isn't for shouting, only to emphasis the importance of the core statement. Best, |
| electr_peter:
In Siglent PSU's series/parallel modes (based on manual) are primarily intended to double voltage/current capability and reduce wire clutter (wiring reconfigured via relays instead of externally). Tracking +/- supply (3 output terminals) is slightly different concept than two channels merged to one channel at 2x voltage (2 output terminals). I think this concept difference leads to different implementations of voltage/current displays when in series mode (one channel HV PSU vs +/- PSU). In other words, full control of +/- supply may be easier to achieve in normal (independent) mode than in series mode. |
| mawyatt:
--- Quote from: electr_peter on October 12, 2024, 07:07:57 pm ---In Siglent PSU's series/parallel modes (based on manual) are primarily intended to double voltage/current capability and reduce wire clutter (wiring reconfigured via relays instead of externally). Tracking +/- supply (3 output terminals) is slightly different concept than two channels merged to one channel at 2x voltage (2 output terminals). I think this concept difference leads to different implementations of voltage/current displays when in series mode (one channel HV PSU vs +/- PSU). In other words, full control of +/- supply may be easier to achieve in normal (independent) mode than in series mode. --- End quote --- Good points about the Intended Usage wrt the SPD3303X, as this design is much older and maybe the designers didn't anticipate the Dual Tracking Split supply use. Actually the solution is simple as they just need to implement as CH2 current reading and that's about it, maybe someone from Siglent is watching ;) The GPP4323 is also an older design but implements the Series Mode exactly as we expect, measuring and showing both CH1 and CH2 Voltage and Current readings, no surprises here :-+ The new SPD4000X should take a serious look at how it's implemented tho, this seems like potential issues lurking as we've discussed. Best, |
| radar_macgyver:
The TTI MX100TP has three outputs. It offers the following tracking modes: V3=V2=V1, V2=V1, V3=V2. Engaging these disables the voltage controls of the secondary rails. For example, setting V3=V2 disables the voltage control of V3 and it instead tracks the voltage of V2. None of these modes internally connect the terminals together, that must be done externally. In all cases, the voltage and current readings are available on all channels. I was surprised to see that with V2=V1 and a load connected to V1 causing it to enter CC mode, the voltage on V2 did not drop to match V1. Therefore, it's not a true 'tracking' supply, but one where the setpoints are matched. The supply also offers several of ranges, some of which internally connect the three channels in series or parallel. One can get 16V/6A, 35V/6A*, 35V/3A, 70V/1.5A, 70V/3A*. The ranges marked with a * internally connect the channels. Voltage/current readouts are hidden for channels that are 'lost' due to the paralleling. |
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