# Overheat protection sensor delay

**URL:** <https://forum.xod.io/t/overheat-protection-sensor-delay/4474>\
**Category:** XOD Programming Questions\
**Created:** [October 2, 2020, 5:17pm UTC](https://forum.xod.io/t/overheat-protection-sensor-delay/4474 "2020-10-02T17:17:38Z")\
**Posts on this page:** 4\
**Page:** 1

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**Author:** ![rusalkin](https://avatars.discourse-cdn.com/v4/letter/r/f0a364/32.png) [@rusalkin](https://forum.xod.io/u/rusalkin)\
**Post date:** [October 2, 2020, 5:17pm UTC](https://forum.xod.io/t/overheat-protection-sensor-delay/4474/1 "2020-10-02T17:17:38Z")

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cant figure this out,  
i have a relay that flips when the temp sensor rises above 50c  
but it then just cools down and starts bouncing between 49.9 and 50  
on off on off, killing the relay

i cant figure out how to let it wait half an hour before it tries taking a reading again and remaining off

 ![gls](https://canada1.discourse-cdn.com/flex027/uploads/xod/original/2X/8/81182c2b92f44043df006a01d529ffe26be35a0c.png)

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**Author:** ![gweimer](https://avatars.discourse-cdn.com/v4/letter/g/a9adbd/32.png) [@gweimer](https://forum.xod.io/u/gweimer)\
**Post date:** [October 2, 2020, 6:02pm UTC](https://forum.xod.io/t/overheat-protection-sensor-delay/4474/3 "2020-10-02T18:02:10Z")

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The clock is just sending pulses every IVAL seconds, so there’s really no reason to RST it. Sounds like you want clock to be enabled only when delay is not active. You can do that using delay-ACT \> “not” \> defer \> clock-EN.

I’m not sure you really want delay activated by delay-ACK. That will also cause delay after heater turns on as well as off. You could link “less” \> pulse-on-false \> delay-SET instead of using relay-ACK.

A “safer” option (if you don’t want things getting too cold) is to turn off above 50, but wait until something lower (like 45) to turn back on.  
 ![image](https://canada1.discourse-cdn.com/flex027/uploads/xod/original/2X/4/45a425c354908bef175f8c28dba73522a287b16a.png)

If it still pulses on/off too rapidly, your temperature probe is too close to the heater or you are measuring the wrong place (for example, if you are circulating a small amount of water to heat from a large tank, don’t measure the small volume just after the heater; as soon as the heater turns off, you are measuring cold water from the tank again; measure before the heater or from the tank).

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**Author:** ![rusalkin](https://avatars.discourse-cdn.com/v4/letter/r/f0a364/32.png) [@rusalkin](https://forum.xod.io/u/rusalkin)\
**Post date:** [October 2, 2020, 6:32pm UTC](https://forum.xod.io/t/overheat-protection-sensor-delay/4474/4 "2020-10-02T18:32:46Z")

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thank you so much, the safer option is very elegant

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**Author:** ![system](https://canada1.discourse-cdn.com/flex027/uploads/xod/original/1X/eb7348baa04192c2ef932d1db54d44f09f8a7888.png) [@system](https://forum.xod.io/u/system)\
**Post date:** [October 4, 2020, 6:32pm UTC](https://forum.xod.io/t/overheat-protection-sensor-delay/4474/5 "2020-10-04T18:32:49Z")

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