The fuses on the I/O cards of the central control unit keep blowing out
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The fuses on the I/O cards in our control system keep blowing; the one that was just replaced blew again after just a few minutes. What could be causing this?
It should be the 24V fuse for the DI or DO card. If that is the case, it is necessary to check whether there is any short circuit in the circuit connected to that card or that card channel. Generally, a short circuit causes high current, which burns out the fuse
It’s best to add isolation; burning like this won’t work.
After installing the fuse, measure the current level first; based on this, it is possible to estimate the reasons that may cause an increase in current. Check the insulation of the card holders with respect to the cabinet, the insulation of the electrical cables with respect to the ground, and whether there is any grounding issue with the on-site instruments.
What exactly is the insurance that the poster is referring to? Is it a fuse for each I/O channel? You can look into peripheral devices more thoroughly. If it’s due to a system issue, it’s probably related to grounding.
What exactly is the insurance that the poster is referring to? Is it a fuse for each I/O channel? You can look into peripheral devices more thoroughly. If it’s due to a system issue, it’s probably related to grounding.
There must be a short circuit somewhere. It would be best if isolation could be added. But, the priority is to find where the short circuit is. It is recommended to mark all the wiring first, then remove it, and finally install the fuse ； Connect one set of wires, wait for 1 minute; if there is no burning, connect the second set, and so on. Until all the short-circuit signals are found and the short-circuit issue is resolved·~~~~ All signals here must pass through a safety barrier; at the very least, they go through fuse terminals
This post was last edited by oatobnus on 2009-11-7 13:14: \"The fuses of the I/O cards in the control unit keep blowing\": It’s best to add isolation...
Burning is definitely not normal; the poster should check the peripheral devices and wiring, and stop replacing fuses all the time!
Is the digital signal sent to the field at 24V voltage +, -, or are both + and - outputs provided by modules? If + goes straight to the site, problems are likely to arise.
1. Check whether the circuit current is greater than the rating of the fuse. 2. Check for any short circuits or ground connections at the instrument terminals