Has anyone had a problem with a temp probe measuring correctly, then suddenly going to 0? I had this problem this past weekend while I was recirculating my boil (over 200 degrees). It was measuring temp fine, then went to 0. I have seen the probe measure quite a bit lower than it should due to an air bubble in the line that was trapped at the top of the probe (mounted vertically). Could this have anything to do with the 0 measurement? I got it back working by loosening the compression fitting to allow any air bubble out, restarting the controller, and restarting my browser. Not sure which one fixed it, if any. My antivirus was off as well, so that shouldn't be a problem. Usually if its a communication problem, I see a N/A on the temp probes.
Thanks for the help!
Temp probe showing 0 degrees
Re: Temp probe showing 0 degrees
A reading of 0deg means that the probe is disconnected. I would double check for loose wires at the connector, and make sure the connector is properly fitting to the controller.
If you are still seeing issues, here are some more tips to track the root cause down:
http://www.embeddedcontrolconcepts.com/ ... reads_Zero
If you are still seeing issues, here are some more tips to track the root cause down:
http://www.embeddedcontrolconcepts.com/ ... reads_Zero
Re: Temp probe showing 0 degrees
OK, so I've given this issue a few more brews and have updated symptoms...
My setup:
Mash tun false bottom to March pump, to electric heat exchanger (hot water heater element running on 120V in a 1.5" stainless steel pipe). From heat exchanger to brass value to brass "T". One side is the probe and the other is the outlet to the top of the mash. All of the hoses are high temp Si hoses.
I also use the same path to recirc the wort in the brew kettle.
When I test with water, the probe works flawlessly.
When recirc mash, the probe works fine, 75% of the time. Sometimes, it will read 20-25 degrees low.
I can touch the probe with the tip of my knife or a screwdriver and it'll immediately return to the correct temp.
When recir boil, the probe will not read above 175 degrees, and varies wildly from 140 to 175. Somestimes going to 0. I mess around with it until it comes back, but I have no idea what I did to make it return.
I can touch the probe with the tip of my knife or a screwdriver and the probe will go crazy. It may come back to working (175 measure of a boiling liquid), may go to 0...
I am almost wondering if it could be a charge buildup issue and when I touch the probe it discharges it enough to start functioning. Could it be due to flowing hot wort through the system? The probe is mounted to a brass T and a brass valve, but isolated from the system, other than the liquid. The ground of the probe is run back to the BCS.
I do have a probe in my HLT, which is completely isolated from the rest of the system. Its mounted to the side of the SS keg. I have never had a problem with that probe. I have also switched probes and both have the problem in the recirc path for the mash and boil.
Any other advise? Should I ground the brass T? I am at a loss at this point, and this is very frustrating...
Thanks for your help!
My setup:
Mash tun false bottom to March pump, to electric heat exchanger (hot water heater element running on 120V in a 1.5" stainless steel pipe). From heat exchanger to brass value to brass "T". One side is the probe and the other is the outlet to the top of the mash. All of the hoses are high temp Si hoses.
I also use the same path to recirc the wort in the brew kettle.
When I test with water, the probe works flawlessly.
When recirc mash, the probe works fine, 75% of the time. Sometimes, it will read 20-25 degrees low.
I can touch the probe with the tip of my knife or a screwdriver and it'll immediately return to the correct temp.
When recir boil, the probe will not read above 175 degrees, and varies wildly from 140 to 175. Somestimes going to 0. I mess around with it until it comes back, but I have no idea what I did to make it return.
I can touch the probe with the tip of my knife or a screwdriver and the probe will go crazy. It may come back to working (175 measure of a boiling liquid), may go to 0...
I am almost wondering if it could be a charge buildup issue and when I touch the probe it discharges it enough to start functioning. Could it be due to flowing hot wort through the system? The probe is mounted to a brass T and a brass valve, but isolated from the system, other than the liquid. The ground of the probe is run back to the BCS.
I do have a probe in my HLT, which is completely isolated from the rest of the system. Its mounted to the side of the SS keg. I have never had a problem with that probe. I have also switched probes and both have the problem in the recirc path for the mash and boil.
Any other advise? Should I ground the brass T? I am at a loss at this point, and this is very frustrating...
Thanks for your help!
Re: Temp probe showing 0 degrees
Hmm, this might be some type of ground loop problem. If you are using separate circuits for different outputs (pump, heater, BCS), make sure that they are all grounded to a common spot. We typically don't recommend tying the BCS GND pin to chassis ground, but you could try it (or disconnect it if you are already connecting it).
Its interesting that you still see the issue when you swap over your HLT probe. I think your idea of grounding the brass T is worrh a try.
Its interesting that you still see the issue when you swap over your HLT probe. I think your idea of grounding the brass T is worrh a try.
Re: Temp probe showing 0 degrees
Last night, I had a buddy come over and we did a full set of experiments on the system... (needed his help b/c my EE degree taught me to stay below 12VDC and usually over 400 MHz... 
). We did find a few problems...
1. There was ~30 VAC on the kegs, heat exchanger, and even the liquid... The HLT didn't have anything on it, but its totally isolated other than the temp probe. This looks like it was the cause of the probe being a few degrees off in accuracy. I calibrated another digital thermometer at work with a high precision temp reference... The BCS probe was 2-4 degrees off. We wired the ground of the BCS to the AC ground and the probe was then accurate to within 0.1 degrees. We did find that the output of the wall transformer of the BCS was supplying the dirty ground. I found another transformer around the house and measured it as well. It had the same AC signature on the ground, but at a lower amplitude (~15 VAC)
2. When the liquid temp got over 155 degrees, the measured temps would go wild... it would actually drop to 135 from 155 degrees instantaneously. At that point, we disconnected the probe and measured the impedance... it was ~14 Kohms. While measuring, I touched the probe and it immediately went down to ~8 Kohms. I replaced the probe, and the gross errors were immediately corrected. I ran it for a few hours, moving temp from 55 to boiling (~208) and didn't see any issues.
So, I am fully up and running now, but probably need to get another probe, as I used my spare. I'm looking forward to my next brew now... Thanks for the help and advice.
). We did find a few problems...1. There was ~30 VAC on the kegs, heat exchanger, and even the liquid... The HLT didn't have anything on it, but its totally isolated other than the temp probe. This looks like it was the cause of the probe being a few degrees off in accuracy. I calibrated another digital thermometer at work with a high precision temp reference... The BCS probe was 2-4 degrees off. We wired the ground of the BCS to the AC ground and the probe was then accurate to within 0.1 degrees. We did find that the output of the wall transformer of the BCS was supplying the dirty ground. I found another transformer around the house and measured it as well. It had the same AC signature on the ground, but at a lower amplitude (~15 VAC)
2. When the liquid temp got over 155 degrees, the measured temps would go wild... it would actually drop to 135 from 155 degrees instantaneously. At that point, we disconnected the probe and measured the impedance... it was ~14 Kohms. While measuring, I touched the probe and it immediately went down to ~8 Kohms. I replaced the probe, and the gross errors were immediately corrected. I ran it for a few hours, moving temp from 55 to boiling (~208) and didn't see any issues.
So, I am fully up and running now, but probably need to get another probe, as I used my spare. I'm looking forward to my next brew now... Thanks for the help and advice.
Re: Temp probe showing 0 degrees
Great! I'm glad that you're up and running.
It makes sense that the BCS gnd is 'dirty' if not connected to the AC ground since the transformer only has two prongs (no gnd). But that's usually ok, since everything that the BCS interfaces with is isolated... i.e., it only measures against its own internal reference.
It almost sounds like the temperature probe had a short from one of its sensor leads to the probe housing, which would explain the erroneous readings. But that wouldn't explain how you could swap probes from your HLT and see the same readings on a different probe. Regardless, I'm happy that you are seeing the expected temperature accuracies now!
It makes sense that the BCS gnd is 'dirty' if not connected to the AC ground since the transformer only has two prongs (no gnd). But that's usually ok, since everything that the BCS interfaces with is isolated... i.e., it only measures against its own internal reference.
It almost sounds like the temperature probe had a short from one of its sensor leads to the probe housing, which would explain the erroneous readings. But that wouldn't explain how you could swap probes from your HLT and see the same readings on a different probe. Regardless, I'm happy that you are seeing the expected temperature accuracies now!
Re: Temp probe showing 0 degrees
Hi,
I am a newbie and just got my BCS 460 and 3 temperature sensors. Too test, I dangled the tip of the 4" sensor into water in my boil kettle that has an analog thermometer. I started to heat the water and it was dead on - I was very excited. But then I started to see what the other posts mentioned. The readings started to vary widely after reaching 130 degrees. Then after a little more time it went dead reading zeros. Ok, maybe I just got a bad sensor. I tried my second one, a 6" sensor, and it was measuring fine until about 90 degrees, then zero, nothing. Neither sensor is working now and I am very baffled. Do I have a bad controller or just happened to get two bad sensors? I was using the temp0 and gnd pins each time. I am afraid to burn up my last sensor, so I would like to find out whats wrong first. Any ideas/suggestions?
Thanks,
Jay
I am a newbie and just got my BCS 460 and 3 temperature sensors. Too test, I dangled the tip of the 4" sensor into water in my boil kettle that has an analog thermometer. I started to heat the water and it was dead on - I was very excited. But then I started to see what the other posts mentioned. The readings started to vary widely after reaching 130 degrees. Then after a little more time it went dead reading zeros. Ok, maybe I just got a bad sensor. I tried my second one, a 6" sensor, and it was measuring fine until about 90 degrees, then zero, nothing. Neither sensor is working now and I am very baffled. Do I have a bad controller or just happened to get two bad sensors? I was using the temp0 and gnd pins each time. I am afraid to burn up my last sensor, so I would like to find out whats wrong first. Any ideas/suggestions?
Thanks,
Jay
Re: Temp probe showing 0 degrees
Jay, please try this:
http://www.embeddedcontrolconcepts.com/ ... reads_Zero
Don't worry about burning up a sensor. Those things are very rugged and should survive anything, except maybe shorting it to 120v. And in that case the controller will probably go before the sensor.
If your probes or controller are bad, we'll obviously replace them. Just send me a PM after you do the experiment in the wiki FAQ.
http://www.embeddedcontrolconcepts.com/ ... reads_Zero
Don't worry about burning up a sensor. Those things are very rugged and should survive anything, except maybe shorting it to 120v. And in that case the controller will probably go before the sensor.
If your probes or controller are bad, we'll obviously replace them. Just send me a PM after you do the experiment in the wiki FAQ.