24V input to PAC.

Why is it that the PAC only accepts 24VAC for RS232 operation? I have a perfectly good 24VDC garage door PSU that I could have used for this but now I have to get an external PSU to power the PAC serial ports. Some of my other 'non-clipsal' management modules accept a wide range input, usually 9-32VAC/DC. That said, I could 'hack' the garage door PSU to feed the 24VAC (well probably a bit more) from there into the PAC but I would have prefered the DC side.

Can it not be changed for a future product update to accept both types? My gutt feel is that I can stick a 24VDC supply on there with a small chance of damage, I just don't know how tricky your AC/DC converter is on the inside. Also, if I do take the +24VAC from the garage door PSU's AC side, what is the upper limit the PAC can handle, I don't want to send 28VAC, or more, to it to find out it has blown up.

Thanks,
Ingo

 

The RS-232 power on the PAC requires a 24Vac connection only. This is used to generate +/- 12V rails for the RS-232 comms. Whilst hooking up a 24Vdc power supply may not fry things, it definitely won't work, since the negative voltage rail for RS-232 won't be established.

If powering the 24V side of the unit is a problem, you could consider powering the RS-232 circuitry over the RS-232 handshaking lines. You do this by using the DTR and RTS lines and putting one high and the other low. Page 7 of the Installation Instructions gives you the pin-outs.

 

Thanks Newman, that -12V rail was the showstopper. The DTR/RTS was my next option to look at.

Ingo

 

I think you meant 24v AC ..

http://www.jaycar.com.au/productView.asp?ID=MP3032&keywords=24v+AC&form=KEYWORD