Rs232 + pac

I've been using PAC to control Somfy blinds for about 5 years without issue, but the 24VAC plug pack connected to the PAC died yesterday.

Have since replaced it but the PAC no-longer sends out RS232.

The Scenes and other logic on the PAC still work ok and I can connect to it ok with Toolkit.

Could the 24v circuitry used by RS232 have been damaged or if it was, would I expect the entire PAC to cease to function?

Is there any way I can test the RS232 side of things on the PAC - something in the logs I should be looking for?

Cheers
James

 

The 24V supply on the PAC is only used for the RS-232 side of the unit. It's quite possible for this to be damaged without affecting the operation of the rest of the unit. Since you've said that you had a power supply die, then it's possible that at the time it died the output of the supply jumped up, even briefly, and damaged the PAC.

The easiest way to test the RS-232 is to feed it's output into a PC. An even better way is to look at the waveforms using a CRO if you can get access to one.

 

Thanks Newman

Haven't seen any output on a PC either ... going to try a different 24v AC adapter now (am hoping that it's the power supply and not the PAC)

 

Probably not recommended but I also blew the rs232 outoput on pac somehow but I managed to find the ttl level outputs inside the pac itself on its micro chip and connected those directly to my own convertor bypassing the pac conversion circuitry. Works fine now for over a year!

 

Hi,

I have had multiple issues with the RS232 drivers on PAC units. They seem to be incredibly sensitive to variations in supply voltage and also to short circuits on the data lines. I have had three go in the last year or so, including one this morning!

On all occasions I have confirmed the fault using an oscilloscope... seems to me to be the only definitive test.

Towbar, out of interest, would you be able to identify the TTL pins - I might be able to bring a couple of these units back from the dead!

Kind regards

Jon