External Moderators Nacho Posted July 11, 2012 External Moderators Report Share Posted July 11, 2012 I have some problems with analog SSR (Celduc, Carlo-Gavazzi, etc brands) when I try to control from an 4-20mA analog output of OPLC. For example with the V200-18-E2B the load impedance is 500Ω maximum for current output. The input dynamic impedance of the SSR is ≥ 100 Ω but a drop in voltage ≤ 8 VDC @ 20 mA. The application doesn't work from 4-8mA, I suppose the dynamic impedance of the SSR will be higger than 500Ω. I found one solution to use several SSR with an analog output, inserting a Power Suply between the output and the SSR. Do you use it any time? does it secure for the analog output of Unitronics? Look at the image: Quote Link to comment Share on other sites More sharing options...
Damian Posted July 11, 2012 Report Share Posted July 11, 2012 Can you provide the exact part number of the SSR? Quote Link to comment Share on other sites More sharing options...
External Moderators Nacho Posted July 13, 2012 Author External Moderators Report Share Posted July 13, 2012 Carlo Gavazzi: RJ1P23I50E RM1E48I50E SSR doesn't work with 4 - 7.2 mA Quote Link to comment Share on other sites More sharing options...
Damian Posted July 13, 2012 Report Share Posted July 13, 2012 Carlo Gavazzi: RJ1P23I50E RM1E48I50E SSR doesn't work with 4 - 7.2 mA RM1E48I50E isn't coming up as a valid part number. Do you have a link to the data sheet? Quote Link to comment Share on other sites More sharing options...
Damian Posted July 14, 2012 Report Share Posted July 14, 2012 Calculating things out for the RJ1P puts the impedance of the SSR right at 500ohm. And you pointed out, the Unitronics is looking for < 500ohm. 500 ohms is pretty typical across all manufacturers for a max impendance for an output like this. I would point the finger more so at Carlo in this case. They shouldn't have to design it with so much impedance. The power supply is a valid solution, but I think I would put more effort into finding better SSRs. Quote Link to comment Share on other sites More sharing options...
External Moderators Nacho Posted July 17, 2012 Author External Moderators Report Share Posted July 17, 2012 OK, I have never had problems with SSR of ERO ELECTRONIC, CONTINENTAL, FUJI ELECTRIC. The end customer have this kind of low cost SSR but they works well with Toho Controllers. Well, I think the idea of the power suply to solve the drop in voltage of the cheap SSR will be the solution. Quote Link to comment Share on other sites More sharing options...
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