Sorry, you need to tell more about the 230 Vac device.
You definitely need to separate the PC common from any mains. If the device contains its own transformer and earth connection, then it's probably permissible to connect directly from one system's logic to the other.
If the device does not have its own isolation from the mains then optical coupling is necessary but possibly not sufficient.
IF all the signals in and out of the Port at TTL logic levels, that is, 0V to +5V, as you are using an isolation transformer with a regulator, no opto-isolators are required.
IF the logic/devices that you have connected are switching mains or high voltage devices then opto-isolators should be used.
this issue isn't completely about what is being controlled. There are many sources of ESD (or worse). The farther the device is from the computer, the more likely something nasty will find it's way down the wire. Just walking around on a low humidity day can build up a huge static charge. use isolation as a mater of good, defensive design.
this issue isn't completely about what is being controlled. There are many sources of ESD (or worse). The farther the device is from the computer, the more likely something nasty will find it's way down the wire. Just walking around on a low humidity day can build up a huge static charge. use isolation as a mater of good, defensive design.
I can't disagree but thought the discussion was about the need for isolation. While isolation may provide some protection to a user, it's main purpose is to prevent damage to electronic devices. GFIs, fuses, breakers and proper wiring are more important for life safety.
I can't disagree but thought the discussion was about the need for isolation. While isolation may provide some protection to a user, it's main purpose is to prevent damage to electronic devices. GFIs, fuses, breakers and proper wiring are more important for life safety.
Extract from an OP's post. The device will contain a 230V/18 V AC step down transformer. The voltage will be rectifed and regulated to 5 V DC using a 7805 regulator IC.
I see that we agree in principle, but as the OP's posts are not clear in how these devices will be connected,
I would prefer to err on the side of caution with my replies.
IMO the use of isolation is to protect users, GFI's and proper wiring are essential, but fuses or breakers will not protect a user,
they will protect the equipment.