I have used magnetic/mechanical relays for years. On a whim I hooked up a solid state relay. The program works fine. The light on the relay module comes on and off fine and correctly.
But when I check continuity nothing is happening? I have not wired the relay to anything. It is brand new and I tested three of them. Does the switch/relay need a load to come on?
// Introduction to 5v Solid State relay.
int relayPin = 8;// set pin 8 for relay output
// setup code for Robojax Solid State Relay
void setup() {
// initialize serial communication at 9600 bits per second:
Serial.begin(9600);
Serial.println("Robojax Solid State Relay ");
pinMode(relayPin, OUTPUT);
}
// loop code for Robojax Solid State Relay
void loop() {
// Turn the relay switch ON (Robojax.com/learn/arduino)
digitalWrite(relayPin, LOW);// set relay pin to low
Serial.println("Relay ON ");
delay(2000);
// Turn the relay switch OFF (Robojax.com/learn/arduino)
digitalWrite(relayPin, HIGH);// set relay pin to HIGH
Serial.println("Relay OFF ");
delay(2000);
}
Hi,
What is written on the SSRs.
Are they AC or DC SSRs.
As this is a solid state switch you will not necessarily be able to measure any continuity.
If you try a power supply and load, you will see it operating.
msgarduino:
Does the switch/relay need a load to come on?
Yes.
At the very least you would need to use the "diode test" function on your multimeter as there is a voltage drop in the "solid state relay". That is why they require heatsinking.
Not sure that "High Level Trigger" has any meaning for a SSR.
It all depends what sort of SSR. Some use MOSFETs which are low resistance when on, some use
triacs which have a voltage drop when on and only hold on if a certain amount of current flows.
triacs are AC only, MOSFET SSRs can be either DC or AC depending on the internal topology.
You might just try a real load... Nothing bad should happen unless you exceed the voltage or current specs.
Some SSRs have a minimum voltage (so it might not turn-on with an Ohmmeter) and some (all?) have leakage (so it might not turn-off with a low-current load) .
AC & DC SSRs are not generally interchangeable. That's an AC relay so it might be built with a TRIAC, and a TRIAC won't turn-off until current goes to zero (at the next AC zero-crossing).
On a whim I hooked up a solid state relay. The program works fine. The light on the relay module comes on and off fine and correctly.
Yes, the led is turning on.
But when I check continuity nothing is happening? I have not wired the relay to anything. It is brand new and I tested three of them. Does the switch/relay need a load to come on?
So where is the schematic showing how you wired it ?
It is on, but you can't measure it. You have to connect a load. (I assume you already know how to wire an SSR)
You can't measure continuity of an SSR because on one side it is an led and on the other side of the 5000V isolation photonic barrier it is a photo activated triac, which would read open if you tried to measure the continuity.
Not sure why you care if it works...
The info in the datasheet has all the hallmarks of a TRIAC.
The datasheet gives a load of 0.1-2A and a load voltage of 75-264V AC. Both the 0.1A and 75V are well above what a normal multimeter delivers.
TRIACs have a minimum current to remain on (if it's too low, they switch off, that's the whole reason of using the things), and the internal switching circuit may require a certain minimum input voltage to give sufficient voltage/charge on the gate for a TRIAC to even switch on.
