PR2B-16-1A have weird response on I2C scan

fenixnano · May 21, 2019, 10:01pm

I just purchased a 8 channel dpdt relay (PR16-4-1A) and a 32 channel relay board PR2B-16-1A.
I connected the 8 channel board to computer by the USB Interface Adapter for NCD IoT Devices Virtual COM Port FT230XS. then connect the 32 channel board to the 8 channel board by I2C cable.

the 8 channel board can be recognized and controlled by the computer using the anyI2C program, the address would always be 39. the relays are working.

yet when I plug the 32 channel board and perform I2C scan, everytime it would be different address. and the board won’t respond to the commands.
occasionally, a few relays would be turn on during the I2C scan, but still won’t respond to the commands

I also tried to use arduino to control the relay board and it’s also not working.

would there be a hardware issue or I messed something in the setup?
Thank you.

fenixnano · May 21, 2019, 10:02pm

new user can only upload 3 images, so I attach another one here

ryan · May 22, 2019, 2:08pm

Please check the jumpers on the relay board to see if they are installed properly.
If they are, please take a photo of the relay board near the jumpers and upload so we can review your jumper settings.
Thanks,
Ryan

fenixnano · May 23, 2019, 1:20am

Hi Ryan,
by jumpers do you mean these?
I didn’t touch them, they came as this.

fenixnano · May 23, 2019, 6:00pm

Hi please check my previous reply, I accidentally replied to the main post instead of yours.

ryan · May 23, 2019, 6:05pm

Are you familiar with I2C device addressing by any chance? These jumpers are used to set the address and it is very important to avoid conflicting addresses. Each device, every relay bank, must have a unique address number or conflicts will occur.

fenixnano · May 23, 2019, 6:22pm

sorry I’m pretty new to this.
is there a tutorial on this?

ryan · May 23, 2019, 7:08pm

We do not have any tutorials on I2C communications as this is very well covered by many other web sites. This is one of the better tutorials on I2C communications I have seen: