Hi!

First of all I apologise in advance if this is not the place to write this post... I'm new to this forum...

This year, I started studies in industrial automation, and I was given and old LOGO! to tinker with, the model being 230RL 6ED1053-1FA00-0BA0, lanched in the late 1990s (1996 - 1998 ?).

While testing it, I noticed that the relays of outputs 1 through 4 didn't "kick in" even though the LOGO screen said that these outputs were activated. These outputs either do not work at all or they barely work very sporadically when the logo is moved, as if there was some sort of bad contact which prevented the relay coils to get the 24V they need to make the commutation. The thing is I can't trace it... Also relays from Q5 to Q8 seem to work fine though.

Thank you so much in advance :)

Thanks for the reply! I think it is the relays not switching, I couldn't see any voltage on the coils... 

Yes it is quite old indeed! At school we work with S7-1200s and with the new LOGOs, they are much better of course, worlds apart from this LOGO!

Yes, what I did, was opening the LOGO and, while running I checked if the internal coils of the relays were receiving voltage, if they were being energised. It seems that, for the relay to switch, the relay coil needs to receive 24V, I think (don't know for sure...) that, when the processor IC gives the order to activate the relay, it activates a transistor or something which, in turn, gives 24V to the relay coil, which, in turn switches the contacts.

The thing is I can't find the 24V anywhere on relay coils 1-4, even though I found the 24V on relay coils 5-8.

Again thanks so much for all the help :)