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sinara-hw / Thermostat_EEM

Thermostat with 4 TEC and 8 sensor channels in EEM form factor
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module specification #1

Closed gkasprow closed 3 years ago

gkasprow commented 4 years ago

@jordens

jordens commented 4 years ago
  • Do we need PoE?

Not strictly need it if causes problems. But it fits the power envelope and would play nicely with the rest of the hardware.

  • I assume that we can connect all AFEs to the same SPI interface, 4 chips per SPI

Yes.

  • DACs will share same SPI interfaces - two chips per SPI

Yes.

  • do we need individual PWMs for each TEC channel?

You mean one MAX1968 per TEC? Yes. Or do you mean the I/V limit PWMs? Those can be banked, let's say two TECs per set of voltages. But let's try to keep them as separate as possible. But I might be misunderstanding you.

  • I assume we want a downstream/upsteream EEM channel like in the Stabilizer. Was it tested already?

With Stabilizer not that I know of. With Humpback and Urukul yes. If there are space/pin problems, I'd rather drop the EEM connector but keep PoE.

  • what connectors? We can use ribbons with DSUB placed on separate panels as in the original Thermostat. But this takes a lot of space. We can also use HD DSUB and have 2 TECs and 4 sensors in each HDSUB15. In this way, noone will mix them with Thermostat or RS232 :) These days nobody is using VGA.

I'm only waiting for someone to connect a monitor to a Booster main board ;)

Do you mean DE-15? Fine with me. @j-hirsch and FBH should weigh in.

gkasprow commented 4 years ago

I tried but in case of DE-15 we don't have enough pins. We won't fit two DA-26 Let's use one DB-44 (High Density D-SUB) which has enough pins and there are ready to use extension cables available. I will design a breakout board to make testing easier

gkasprow commented 4 years ago

The pinout could be as follows obraz

gkasprow commented 3 years ago

It looks like we will have individual PWM channels for all TEC driver settings.

gkasprow commented 3 years ago

Initial placement obraz

jordens commented 3 years ago

When running one big tec from two channels in parallel, would we connect them on the header board?

gkasprow commented 3 years ago

I'm not 100% sure if you can easily run two channels in parallel. These are synchronous converters - even a small differences in duty cycle will result in high cross-current flowing within the pair of shorted outputs. The header board is for debugging purposes.

jordens commented 3 years ago

Aren't the drivers effectively current sources which should work in parallel? FBH indicated that they need one case with two in parallel. Best to disuss with @j-hirsch @schiemangk.

jordens commented 3 years ago

Alternatively it might be easy to just use two electrically separate half-size TECs to get the same result. Having two smaller independent TECs zones may actually be much better.

hartytp commented 3 years ago

looks nice! Any further thoughts about power/thermal management here? Can you get enough juice out of a single EEM for that many TEC drivers?

jordens commented 3 years ago

It'll need active power management and load sharing anyway. EEM is probably not going to be the use case for us but the connector/cable is probably not going to be the limitation. It's just there because we can.