[CLOSED] ASICMiner Prisma 1.4th/s - 1.47 BTC

[philipma1957]

I'm gonna be setting up some Prismas to host in the next day or two, probably on DPS2K PSUs. Definitely not in load-balanced, which shouldn't be necessary since these boards all have isolated 12V lines. A pair of Prismas shouldn't quite max out a DPS2K, maybe 110% rated. It wouldn't take much of a short to run up to OCP (about 120% rated). Hopefully we don't test that hypothesis with a "live-fire" experiment.

Thanks for the info on what's been going on.

 try a side fan  let it blow air at the side of the units in the middle area.  I am keeping my unit at freq 230 not 240

very good numbers at freq 230   1396     3% errors  power is 1215 watts that is .87 watts at the plug, but I run the added delta fan on the unit the side fans and some other fans .  the extra fans use 15 watts or more.

[CrazyGuy]

If you were a participant of my group buy, please check your PM. Also, I have received contact from AM tonight with a few recommendations.

- Run in a cool environment.
- Use a PSU with overcurrent protection
- Do not run your unit near combustible materials
- Prevent fan failure.

ASICMINER did not mention a second fan, but if you are powering with two PSUs, it might not be a bad idea. Consider the case where two PSUS are powering a unit and the one that is powering the fan trips or fails. At that point, you may have multiple boards still running but with no fan. This actually happened to me, but because I forgot to plug the fan back into the board after messing with dipswitches. I had outside airflow, but the unit eventually just stopped hashing, no meltdown, and it came right back up when I plugged the fan back in. I'm not certain that would always be the case.

I also spoke with a number of engineers and one observation stood out. Most of the heat from each be chip goes downwards towards the heatsink, but there is a small amount that goes outwards towards the surface of the board. If you are running in a hot environment, this heat could build up and be absorbed by other components, capacitors, etc...

[DigitalPackrat]

The thought of a PSU failing on the fan powering board has been scaring me for a while. I will be adding a secondary fan soon just in case but also rewiring the PSU's so a failure on the fan powering board shuts everything down. I can understand AM's viewpoint of the miners not being adequately cooled. They have little knowledge of my setup and I wasn't watching the miners as they failed so it's just best guess as to what happened. All I can say is there was a significant amount of airflow, the incident happened during the peak temperature of the day which was about 75f, there was likely some mixing of outside air with the nearby GPU miners but I think intake temperature would have been 80f at max for the prisma's.

80f isn't ideal for all datacenter conditions but even my in house servers with dedicated AC are only seeing 78. In reality 80f isn't' unheard of for servers. Even Intel has experimented with higher temps for their servers. Realistically, 80f isn't that bad when you consider that most miners are trying for lowest cost which often means cooling miners with outside air vs AC. Take everything as you will. If you are concerned with non conductive barriers, you can get paver stones from your local home improvement store for just a few dollars. It's basically a slab of cement which will absorb a fair amount of heat and has minimal conductivity. You wouldn't have to worry about an arc flash not that it's likely to happen anyways. Just to clear up another question on my setup, there were no signs of arching, there is only some slight surface rust on the scrap sheet metal which has been sitting for years after making a spacer and swapping a transmission into a vehicle it didn't belong in.

In the end, make your own opinions, this is just a engineering perspective from someone that works on 14nm and larger nodes.

[vortexz]

Configuring your Prisma for use with BE or RPI controller:

1) Each physical board has two addresses in a 5 bit address space. Only 4 of those bits are configurable. Boards 01-16 are paired with logical boards 17-32, starting with the first switch configuration(0000). This results in the first physical board having an address of 01 and 17
2) Boards must be chained in incremental order. (Example: 01:17,02:18,03:19,04:20,05:21...)
3) The least significant bit is reversed from the tube, with the tube's last switch,"5", being the least significant bit and the Prisma's first switch ,"1", being the least significant bit. Off and on still refer to 0 and 1 respectively.

Warning: Leave Switch 5 alone! If you set it on for any board, the controller will not see any boards in your chain.


Example switch configuration. ( "X" is OFF, "O" is on)

Board 1: (01:17)
Switch :  1  2  3  4  5
Setting:  X  X  X  X  X

Board 2: (02:18)
Switch :  1  2  3  4  5
Setting:  O  X  X  X  X

Board 3: (03:19)
Switch :  1  2  3  4  5
Setting:  X  O  X  X  X

Board 4: (04:20)
Switch :  1  2  3  4  5
Setting:  O  O  X  X  X

Board 5: (05:21)
Switch :  1  2  3  4  5
Setting:  X  X  O  X  X

Board 6: (06:22)
Switch :  1  2  3  4  5
Setting:  O  X  O  X  X

Board 7: (07:23)
Switch :  1  2  3  4  5
Setting:  X  O  O  X  X

Board 8: (08:24)
Switch :  1  2  3  4  5
Setting:  O  O  O  X  X

Board 9: (09:25)
Switch :  1  2  3  4  5
Setting:  X  X  X  O  X

Board 10: (10:26)
Switch :  1  2  3  4  5
Setting:  O  X  X  O  X

Board 11: (11:27)
Switch :  1  2  3  4  5
Setting:  X  O  X  O  X

Board 12: (12:28)
Switch :  1  2  3  4  5
Setting:  O  O  X  O  X

Board 13: (13:29)
Switch :  1  2  3  4  5
Setting:  X  X  O  O  X

Board 14: (14:30)
Switch :  1  2  3  4  5
Setting:  O  X  O  O  X

Board 15: (15:31)
Switch :  1  2  3  4  5
Setting:  X  O  O  O  X

Board 16: (16:32)
Switch :  1  2  3  4  5
Setting:  O  O  O  O  X
 

Here is daisy chain for only 16 boards, 4 prismas to be connected to 1 controller
Is there any way I can connect 6 prismas (24 boards) to 1 controller ?

[PlanetCrypto]

I'm gonna be setting up some Prismas to host in the next day or two, probably on DPS2K PSUs. Definitely not in load-balanced, which shouldn't be necessary since these boards all have isolated 12V lines. A pair of Prismas shouldn't quite max out a DPS2K, maybe 110% rated. It wouldn't take much of a short to run up to OCP (about 120% rated). Hopefully we don't test that hypothesis with a "live-fire" experiment.

Thanks for the info on what's been going on.

Your calcs are correct if the Prisma's draw as advertised.
They don't.
@ 240 clock rate ours (2x) are drawing ~1250W each.
When OC'd to 250 they draw 1300W each.
When OC'd to 270 they draw ~1400W each.

We are powering one with a DPS1600BB (using your most excellent adapter board) and the other with 2x HP 1000's.
Both are being feed by 8 16ga PCie cables because in our initial test using 4 cables they got more than warm to the touch.

[Chris_Sabian]

If you were a participant of my group buy, please check your PM. Also, I have received contact from AM tonight with a few recommendations.

- Run in a cool environment.
- Use a PSU with overcurrent protection
- Do not run your unit near combustible materials
- Prevent fan failure.

ASICMINER did not mention a second fan, but if you are powering with two PSUs, it might not be a bad idea. Consider the case where two PSUS are powering a unit and the one that is powering the fan trips or fails. At that point, you may have multiple boards still running but with no fan. This actually happened to me, but because I forgot to plug the fan back into the board after messing with dipswitches. I had outside airflow, but the unit eventually just stopped hashing, no meltdown, and it came right back up when I plugged the fan back in. I'm not certain that would always be the case.

I also spoke with a number of engineers and one observation stood out. Most of the heat from each be chip goes downwards towards the heatsink, but there is a small amount that goes outwards towards the surface of the board. If you are running in a hot environment, this heat could build up and be absorbed by other components, capacitors, etc...

What if you put a box fan infront of the miner?  Box fans are rated for ~2,000 CFM and that should help with cooling.  Maybe put some baffles to direct airflow around the miner?

[CrazyGuy]

If you were a participant of my group buy, please check your PM. Also, I have received contact from AM tonight with a few recommendations.

- Run in a cool environment.
- Use a PSU with overcurrent protection
- Do not run your unit near combustible materials
- Prevent fan failure.

ASICMINER did not mention a second fan, but if you are powering with two PSUs, it might not be a bad idea. Consider the case where two PSUS are powering a unit and the one that is powering the fan trips or fails. At that point, you may have multiple boards still running but with no fan. This actually happened to me, but because I forgot to plug the fan back into the board after messing with dipswitches. I had outside airflow, but the unit eventually just stopped hashing, no meltdown, and it came right back up when I plugged the fan back in. I'm not certain that would always be the case.

I also spoke with a number of engineers and one observation stood out. Most of the heat from each be chip goes downwards towards the heatsink, but there is a small amount that goes outwards towards the surface of the board. If you are running in a hot environment, this heat could build up and be absorbed by other components, capacitors, etc...

What if you put a box fan infront of the miner?  Box fans are rated for ~2,000 CFM and that should help with cooling.  Maybe put some baffles to direct airflow around the miner?

I think it is a good idea. This is what I have been doing.

[philipma1957]

well my unit is in my garage.  on a woodbench near the garage door.

it is 40 f outside in NJ  door is open with a fan puling in air



note temps below  not sure it that sensor is in the rasp pi or on the miner. I will now shut the  garage door.  it is 11:11:11 am in NJ



door open fan blowing in.   

[CanaryInTheMine]

well my unit is in my garage.  on a woodbench near the garage door.

it is 40 f outside in NJ  door is open with a fan puling in air



note temps below  not sure it that sensor is in the rasp pi or on the miner. I will now shut the  garage door.  it is 11:11:11 am in NJ



door open fan blowing in.   

Please move that prisma.  You are asking for trouble with it so close to wood.  Too many have caught on fire.

[stan258]

I haven't gone past 210. Might just keep it. That way.

[mrpark]

What is your hash rate @ 210?

I haven't gone past 210. Might just keep it. That way.

[stan258]

What is your hash rate @ 210?

I haven't gone past 210. Might just keep it. That way.

1225Gh. I have a cooling duct aimed right at them.

[stan258]

I did trip a 220/240 pdu when clocked at 240. They may pull a junk load of juice at start up.

Clarification edit: Two Prismas at start up to one PDU. Same PDU that it's brother handles 2 SP 30 no problem. 

[ferncreekminer]

What is your hash rate @ 210?

I haven't gone past 210. Might just keep it. That way.

1225Gh. I have a cooling duct aimed right at them.

I down clocked to 230 - earlier today (about 5 hrs ago) - and added a fan (at 4:05pm on the graph below) blowing on the side of the 2 prismas - wide variance in poolside hashrate - seems better the last hour with fan and clock 230 - Minera Error/Reject Rate @ 3.84

https://i.imgur.com/w729eeT.png

[mrpark]

Try setting the difficulty to a static number if you have not done that already, 1024 seemed to work OK for me on Ghash.io.

What is your hash rate @ 210?

I haven't gone past 210. Might just keep it. That way.

1225Gh. I have a cooling duct aimed right at them.

I down clocked to 230 - earlier today (about 5 hrs ago) - and added a fan (at 4:05pm on the graph below) blowing on the side of the 2 prismas - wide variance in poolside hashrate - seems better the last hour with fan and clock 230 - Minera Error/Reject Rate @ 3.84

[ferncreekminer]

Running @ difficulty 2048 - discoverd that vardif pool ports are bad for my units - if for some reason they drop under 300 -- they will not recover - stop hashing... Happened all the time on the BE Controller; & initially when I went to the Minera RPi image -- haven't switch back to a vardif port since -- pool I mine doesn't have ability to set difficulty.

Try setting the difficulty to a static number if you have not done that already, 1024 seemed to work OK for me on Ghash.io.

What is your hash rate @ 210?

I haven't gone past 210. Might just keep it. That way.

1225Gh. I have a cooling duct aimed right at them.

I down clocked to 230 - earlier today (about 5 hrs ago) - and added a fan (at 4:05pm on the graph below) blowing on the side of the 2 prismas - wide variance in poolside hashrate - seems better the last hour with fan and clock 230 - Minera Error/Reject Rate @ 3.84

https://i.imgur.com/w729eeT.png

[PlanetCrypto]

The Tower of Prisma

Solved a lot cooling issues this way and freed up some rack real estate in the process.
Mounted this way the boards are running about 60F cooler.
On to OC'ing them.

Sorry about the blur, was standing on a chair and I'm an old fart.

[PlanetCrypto]

FYI, if you get a Prisma cold enough the fan will cycle.

[CrazyGuy]

The Tower of Prisma

Solved a lot cooling issues this way and freed up some rack real estate in the process.
Mounted this way the boards are running about 60F cooler.
On to OC'ing them.

Sorry about the blur, was standing on a chair and I'm an old fart.

I like it. I was thinking of something similar the other day, but hanging instead of standing. A Prisma "batcave" of sorts.

[suchmoon]

The Tower of Prisma

Solved a lot cooling issues this way and freed up some rack real estate in the process.
Mounted this way the boards are running about 60F cooler.
On to OC'ing them.

Sorry about the blur, was standing on a chair and I'm an old fart.

https://i.imgur.com/vPCWf16.jpg

Thank you, this looks like a great idea. I think I'm gonna try that too.