C-Bus optocoupler

[hazmoment]

Hey up. Can anyone help with a wee problem Im having. with an optocoupler. Ive Just replaced an Optocoupler and a blown triac out of a C-Bus 8channel dimmer module and managed to get it working but only in the on or off state, I have no dimming. I believe the problem to be with the optocoupler i chose (vishay VO3062) to replace the original IL440-2. To prove that this is the cause of the problem i installed another VO3062 on another known good channel and gave me the same results, But I am not too experienced with optocouplers and what would be causing this behaviour. Can anyone point out the differences between the two which may be the cause of this? Or a more suiting replacement opto!?

https://pdf1.alldatasheet.com/datasheet-pdf/view/114398/VISHAY/IL440-2/+0144--VyhSHwadLPzCNpw+/datasheet.pdf

https://www.vishay.com/docs/83748/vo3062.pdf

Cheers! Hazmoment.

[tsman]

Basic C-Bus dimmers are leading-edge dimmers so the additional zero-crossing circuit in your VO3062 will interfere with it and stop it from dimming correctly. You need an optocoupler without a ZCC.

[hazmoment]

hey thanks! Why have zero crossing current built in to the opto? Any benefit in other applications? I will order a few of another type to try!

[tsman]

It causes less interference and lower inrush current since it'll be switching when the AC waveform is at 0V. They're useful if you just need on/off and not trying to do phase angle control.

[hazmoment]

Gotcha. I have found this opto i hope will do the job seems to match the specs at least as far as i can tell.

https://nz.element14.com/vishay/il420/optocoupler-phototriac-5300vrms/dp/1469561