I am using an Arduino mega to switch several of these very common relays with a 24v inductive load on pretty much all of them and I am having a peculiar and extremely frustrating issue where during switching (frequently but not always) the Arduino will reset, when monitoring the arduino's 5v power rails with oscilloscope there is extreme noise (60v+) during switching the relays but Only when the 24v is applied to the relays, when where is no load the noise/reset does not occur. This was very confusing to me as I understood these voltages to be isolated by the relay module
For this reason I believe my issue is related to the voltage spike created by the inductive load like discussed here
where it says that
but I don't have enough info here to produce a circuit, I have found some mentions of circuits using a diode on the relay coil (5v) side like this but it appears that the board already has a diode in parallel to the coil so I am wondering if there is another similar type of circuit (perhaps on the load side?) or some guidelines on how I should modify the existing circuit to mitigate this?
Note
For this reason I believe my issue is related to the voltage spike created by the inductive load like discussed here
where it says that
- A diode and a resistor (for DC circuits) – the diode as well as the resistor need to be sized according to the switching frequency, spike voltage and the load input power. The diode breakdown voltage must be higher than the circuit supply voltage, and the maximum forward current must be higher than the current through the load (inductor) when switched on.
but I don't have enough info here to produce a circuit, I have found some mentions of circuits using a diode on the relay coil (5v) side like this but it appears that the board already has a diode in parallel to the coil so I am wondering if there is another similar type of circuit (perhaps on the load side?) or some guidelines on how I should modify the existing circuit to mitigate this?
Note
- the relay boards are being powered from a buck converter from the 24v power source, the Arduino is being powered by USB, I have also tried powering the Arduino from the buck converter and powering the relay boards from the Arduino