@rb550f Can you provide a diagram how you connect to ezb i have a similiar 8 relay card

If you have it connected correctly and it isn't latching then it should turn off when you set the port to low.

Double check connections. Vcc to Vcc Ground to Ground Signal pins of Digital Ports to each of the enables

On setting of a port to on or high the relay should close. On setting the port off or low it should open. Presuming you use the normally open pin (normally closed would be the opposite).

I have d15,d16,d17,d18 connected to in1,in2,in3,in4 respectively..i have red led for 5v power on..i set each port on and i get relays green leds light and are on...when i toggle digital ports on all the relays are on.They will not toggle off unless i disconnect each digital port wires..ezb v4...common ground to relay board and ezb...

Here is how I wired a single relay unit and use the set digital on/off commands to operate and release each relay.

That is basically the same setup i have except board has four 5vdc relays.I tried connecting a 5v led and i can toggle it on/off,but cannot toggle relays.They stay on once that digital port is activated.

I have Gnd connected to both VREF and Gnd. Is your board able to use the same electrical connection for Gnd?

Could be an issue with the amount of current needed to control the relay or it could be voltage. The ez-b v4 may not be driving high enough toward 5volts to control the relay. Most of these boards are set up to handle open connections on the relay control pins so they can be connected to devices like arduino whose pins come up open. This usually means they have a load resistor. Not sure how much this one draws on its enable pins, but I have seen some that require 20ma of current. As far as voltage, I haven't seen spec on low and high voltages for the control pins. EZ-B v4 high output is only 3.3volts. Your relay board may need a voltage closer to 5volts to work.

I'm using an EZB(4) but use a voltage regulator to provide +5 vdc to operate the relay.