I intend to measure the response time of relay contacts. The equipment under test (EUT) is a 24V - 3 poles relay. I am using a 4 channels optocoupler to detect 1) when voltage is present at the coil 2) the making of the contacts. I am using an Arduino Nano with LCD (20x4) to display the results. The wiring is simply that input pin 2 will be detecting the output of the optocoupler that is link to coil voltage while pin 3 to 5 are link to the relays contact through the optocoupler respectively. Currently, my approach is that pin 2 will acquires the millis() and store in time0 while the relay contacts will do the same and store that in time1, time2 and time3. I am using the simple "if" statement to check the condition of these 4 inputs.
My question are 1) the EUT usually has a contact response time around 20ms and the time difference between them is probably 1ms. Can the Nano accurately do such computation? 2) Will the contact bouncing affect the acquisition time even i am using an optocoupler?