What does "High Level" mean for these SSR?

Other Hardware General Electronics
1

I have just ordered a couple of these to replace a two-mechanical relays, board that are proving to be unreliable for any length of time.

But now, not sure if the SSR are a drop in replacement or not. Farther down that page is says,

3, the input power supply: 5V DC (160MA)
4, the input control signal voltage:
(the state of the 0-2.5V low level relay OFF)
(the state of the 3-5V high level relay ON)
5, the blue KF301 terminal is connected to the line of control more convenient.
Module interface:
Input part:
DC+: connect the power supply positive (press the relay voltage power supply)
DC-: the cathode of a power supply
CH: relay module signal trigger end (high level trigger effective)

Can I still drive these SSR for small pumps (0.7A and 0.9A) directly from the Nano Data-Pins?

void pumpSet_1(bool setPump) {
  if (setPump) {
    digitalWrite(PIN_PUMP_1,HIGH);
  } else {
    digitalWrite(PIN_PUMP_1,LOW);
  }
}
2

Hi,
MUCH more help if you give a link to the actual SSR.

General HIGH=ON=5V or so LOW=OFF=0V or so.

3

Not enough info.
A "small ~0.8A pump" indicates low voltage.
Most SSR boards are for mains voltage switching, not for low voltage DC.

Why were the mechanical relays unreliable.
If they were used for DC pumps, did you have a kickback diode across the pump?
Leo..

4

Thanks, but I did have a link to the actual SSR board. No idea who removed it, but can guess why, but here it is again.
https://www.amazon.com/gp/product/B00NON2RRY/ref=oh_aui_detailpage_o00_s00?ie=UTF8&psc=1

The pumps are small submersible fountain pumps, 110vac, 0.8A and 0.9A.

5

Hi,
I have some more info on those SSRs on my page HERE:

DISCLAIMER: Mentioned stuff from my own shop... !

You will find the schematic etc there...

6

@terryking228
This seems wrong for a 2-channel board: "5VDC / 160mA (all channel ON)."
Probably taken from an 8-relay board, so could be "20mA per relay".
I doubt it's even that much.
Leo..

7

160mA for the coil is typical. It's not talking about the signal current draw.

3-5V registering as HIGH is also typical for 5V logic, where it's 60% of VCC, in this case 5V.

8

INTP:
160mA for the coil is typical. It's not talking about the signal current draw.

If there was a coil...

9

Right . . . . whoops.

Here's a DS anyway

10

Wawa:
If there was a coil...

With my meter I am unable to read any current at all. I jumpered across from the the 5vdc to the CH-1- and the red LED comes on for each SSR, but not enough current to measure. I am guessing it is not going to eat the Nano then.

As soon as the thing stops running, I will install this board in place of the mechanical relays. All looks hopeful. :slight_smile: