HERMS Controller Crossroads

[Timothy Schwitz]

I've been slowly gathering all of the parts to build an electronic HERMS 3 Keggle system and am getting closer each day.

My Keggles are all set up, HLT and BK with 5,500 heating elements, 2 pumps, the usual build, etc.

Now I'm wondering what to do for the controller. I have read everything I can so far on this board, and some other pages, but am somewhat stuck on where to go from here.

Right now I have the 3 SSR's, the 3 contactors, box, electrical plugs (240 and 120) lights, switches, and all of the temp probes.

Based on the attached picture I would still need to order a good amount of items to go with the Raspberry Pi build.

Based on the information I found on a PID controller, I would still need to order the PID's, and the boil controller. Is there anything else that I would need for that build?

If you have one or the other, why did you decide to go that way vs the other?

I'm OK going with either build, I have an extra Pi laying around, and seems user friendly to set everything up.

Just looking for opinions to push me one way or the other here.

Thanks in advance

 

[doug293cz]

I've been slowly gathering all of the parts to build an electronic HERMS 3 Keggle system and am getting closer each day.

My Keggles are all set up, HLT and BK with 5,500 heating elements, 2 pumps, the usual build, etc.

Now I'm wondering what to do for the controller. I have read everything I can so far on this board, and some other pages, but am somewhat stuck on where to go from here.

Right now I have the 3 SSR's, the 3 contactors, box, electrical plugs (240 and 120) lights, switches, and all of the temp probes.

Based on the attached picture I would still need to order a good amount of items to go with the Raspberry Pi build.

Based on the information I found on a PID controller, I would still need to order the PID's, and the boil controller. Is there anything else that I would need for that build?

If you have one or the other, why did you decide to go that way vs the other?

I'm OK going with either build, I have an extra Pi laying around, and seems user friendly to set everything up.

Just looking for opinions to push me one way or the other here.

Thanks in advance

Not to be cruel, but that design is not very good.

• The element SSRs should be directly modulating the power to the elements, not controlling the element power enable contactor coils. If you want to control the contactors from the RPi, you should use a relay board designed to be driven by the RPi.
• You don't need SSRs or contactors for the pumps. You can drive the pumps directly from the same relay board as used to control the element contactors (if you have enough channels on the relay board.)
• You should always have a manual, mechanical switch that will kill power to the system. Amature written software and RPi hardware is not reliable enough to entrust with safety critical functions.

Here's a design schematic for a HERMS controller that uses PIDs:

Although I would replace the SYL-2352 controlling the HLT with a DSPR320, and the SYL-2352 monitoring mash temp with an Auber SYL-2802B, which would allow measuring temps in two different locations.

Brew on

 

[Timothy Schwitz]

Not to be cruel, but that design is not very good.

• The element SSRs should be directly modulating the power to the elements, not controlling the element power enable contactor coils. If you want to control the contactors from the RPi, you should use a relay board designed to be driven by the RPi.
• You don't need SSRs or contactors for the pumps. You can drive the pumps directly from the same relay board as used to control the element contactors (if you have enough channels on the relay board.)
• You should always have a manual, mechanical switch that will kill power to the system. Amature written software and RPi hardware is not reliable enough to entrust with safety critical functions.

Here's a design schematic for a HERMS controller that uses PIDs:

View attachment 729932

Although I would replace the SYL-2352 controlling the HLT with a DSPR320, and the SYL-2352 monitoring mash temp with an Auber SYL-2802B, which would allow measuring temps in two different locations.

Brew on

That's exactly the advice I was looking for. Thank you!

I've seen your diagrams on other posts and been trying to find the best way to do this.

Appreciate your time!