iarglez Posted November 8, 2006 Report Posted November 8, 2006 Have you ever tried to connect the output of a Solid State Relay to handle a discret input of a PLC? I have two 24V DC discrete inputs been controlled by SSR's, one of them is a 24V DC CONTROL and it switches the 24V DC PLC input (NPN input type, D1D07 crydom p/n) I have no problem with this one. The other one it's a 220V AC CONTROL and it switches 24V DC . The last one is chattering and there is less than 70 V AC on the input terminals (CRYDOM DC60SA3). Does any one have experienced this before??? Thanks! Quote
IO_Rack Posted November 9, 2006 Report Posted November 9, 2006 What is controlling the SSR? That sounds like your problem. Has this application been working? If not then check the output specs on the SSR. If it is a large load then the 24VDC input may not be enought to pull it on. Quote
iarglez Posted November 9, 2006 Author Report Posted November 9, 2006 Well, actually yes. The SSR is not controlling anything but the discrete DC PLC Input. I will connect a resistor as a parallel load and see how it works. The funny thing is that I have no problem with the other SSR (24V DC CONTROL - 24V DC SWITCHING) . Thanks! Quote
ianbuckley Posted November 10, 2006 Report Posted November 10, 2006 As IO_RACK implied, it looks to me like your problem is the 70VAC at the input terminals. Looking at the specs for that relay, 70V is in "no man's land" - below turn on voltage and below turn off voltage. This would likely cause a chatter. Is the whole 220 VAC bus sitting at 70V? That seems unlikley. You may or may not have an issue with load on the output depending on the input impedance, but I would look for a high impedance connection between the 220VAC source and the input terminals to find the 150VAC drop. Quote
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.