I have been experimenting with my wonderful Velleman k8055 and, until now, things have gone smoothly. Now, however, I have tried to get it to turn on some relays but it appears that an AC24V supply, wired to the ‘Clamp’ terminal, is not something that the k8055 enjoys.
The 24V AC relays each consume a current of about 67mA, so are within the current range specified for the outputs.
My initial attempts to run my 24V AC relays were partially successful. I wired the Neutral Terminal of each relay to the various Digital Outputs, and I wired the Neutral terminal of the 24V AC transformer to the GND terminal of the Digital Output block. With this setup, the k8055 successfully activated relays on ‘active’ Ditital Outputs, although it failed to fully turn off the supposedly ‘inactive’ digital outputs (some residual voltage on those ‘inactive’ terminals resulted in the connected relays ‘chattering’ as they attempted to turn on).
Then I connected the 24VAC Active terminal of the transformer to the CLAMP terminal on the k8055. The device no longer works; when I plug in the USB cable, all 8 of the Digital Output LEDs light up, and remain illuminated (though not at full intensity). The k8055 no longer gives the initial 3 flashes of DO8 when I plug it in.
I’m guessing that my attempt to drive AC relays from this board has caused the problems I’m now experiencing. Is there a way to drive these relays directly from the k8055 ?
More immediately, I need to fix my k8055 but don’t know where to start, or which component(s) are likely to have been damaged by the connections I’ve made. I’d welcome some feedback on this.
Please note that the outputs of the K8055 are DC only.
If they have received AC, they will probably be defective.
I hope it has not destroyed any other parts.
Initially I replaced IC4 and this corrected most of the faulty behaviour: LED8 flashed 3 times upon plugging in the USB cable, however, LED1 also switched on, and remained illuminated even when the software commanded DO1 open.
Interestingly too, the board only did its 3 flashes if the USB cable was plugged directly into the computer’s USB outlet; it failed to give the 3 flashes if connected via a USB hub. When plugged in directly, the board appeared to function normally on all DO’s except for DO1.
I then purchased a second k8055 kit and began substituting parts into the faulty board and found that upon replacing IC3 (PIC16C745-1/SP), the kit was restored to fully working order.
Now what I have to do is to get hold of another PIC16C745-1/SP chip so that I can get my second kit working.
Thankyou for your offer. As you say it is not a warranty case, do I include any payment with the chip in order to receive an exchange chip ?
Also, I earlier indicated that the damaged chip works on all DOs but DO1. While this is the case, I noticed that the chip quickly became hot so I ceased further use for fear of burning it out completely.