IMPORTANT ISSUE with bed temp controller

Veti

@jrockland said in IMPORTANT ISSUE with bed temp controller:

Jan 14 01:30:42 raspberrypi DuetControlServer[14574]: [error] Heater 1 fault: temperature excursion exceeded 15.0°C (target 90.0°C, actual 128.2°C)

this suggest a failure of the relay

Luke'sLaboratory

@jrockland said in IMPORTANT ISSUE with bed temp controller:

pberrypi rngd[377]: stats: bits sent to kernel pool: 484096
Jan 14 02:04:45 raspb

My take from this is that it shut down the duet after 10 min of heater fault, and if the relays need a high signal to turn off, by having no signal (from a shut down duet) it just stayed on and caused the issue.

jrockland

@Veti didnt understand the first part but Ill change it to out.0

Veti

@jrockland said in IMPORTANT ISSUE with bed temp controller:

didnt understand the first part

it means your bed will be reporting the wrong temperature.
it will display 100C but it wont be 100C

jrockland

@Luke-sLaboratory I dont know what SSR mean, but they look like normal relays to me.

Veti

@jrockland said in IMPORTANT ISSUE with bed temp controller:

SSR

Solid State Relay.
Using cheap ones is a sure way to burn your house down.

Luke'sLaboratory

@jrockland https://duet3d.dozuki.com/Wiki/Connecting_thermistors_or_PT1000_temperature_sensors - Relevant documentation.

I'd take a serious look at what relays you are using (whether they're SSR's or traditional) the correct switching frequency, which thermistors you actually have in all of your machines, and the configuration of using a high Signal from the duet to turn relays off.

Preferably you'd drop the frequency to ~10hz (by adding a Q10 to your M950 where you set up the output for out3 (or out1)), and reconfigure/aquire new relays that require a high signal from the duet to turn on. That way, if your duet goes offline for whatever reason, your relays will not turn on.

Next I'd definitely recommend high-quality SSRs. Cheap/underrated/undercooled ones will latch on and have the exact behavior that may have caused this issue in the first place. Thats why I was looking for specifics on the relays used.

jrockland

@Luke-sLaboratory the board send a ON signal as soon as I power it up if I remove the "!".. Ill need the tech to look into that asap. seem like it working the wrong way.

Luke'sLaboratory

@jrockland Do you mean that your relay turns on if you take off the ! from the duet config? or is the duet's output turning on when you remove the !

jrockland

@Luke-sLaboratory not the ssr's, im testing the board with a meter right now. relays had been tested and work good.

jrockland

@Veti yea I looked at the picture and it is what we use.

Veti

@jrockland said in IMPORTANT ISSUE with bed temp controller:

yea I looked at the picture and it is what we use.

what picture?

jrockland

@Luke-sLaboratory the relay turn off as soon as they are not fed power

jrockland

@Veti looked online for ssr relays

jrockland

@Veti you are right, they are ntc 3950. Ill have to find out how to change that

Veti

@jrockland said in IMPORTANT ISSUE with bed temp controller:

ntc 3950

they are not the best and become inaccurate at high temperatures.

jrockland

Anyway thank for all the answers, tones of thing to look at;
like why my board seem to work the opposite way ? (compared to my other 6hc's)
Stop.G files (that files is empty ??)
thermistor: wrong model ? (ill have to find how to change that)
port 0.out instead of 3.out (will move some stuff around)
Also I will add an external fail safe (I should had done that long time ago)

Just to reassure anyone, the relays does shut down as soon as I send a M999/M112 or shut the board off. even if they are written as "!out.3".... maybe the connection to the board is wrong.

jay_s_uk

if you use out0 don't forget to add power in for it

jrockland

@Veti I know, but with what I use them for they are easy to get and cheap..: I prototype parts so I actually destroy parts as a daily task. I basically apply change, then run the project until it break. then make it better. I crashed so many hot ends I buy those sensors in 50 packs XD

jrockland

@jay_s_uk wait.. just want to make sure im not wrong here.. i mean C"io0.out".. my bad. too much power out of OUT0.