Posted 16 Nov 2016 Hi I am searching for plc having negative analog input and output. i.e. 0 to -10v analog i/p and Analog o/p. Can any one help me in finding plc which has this feature . Thank You Share this post Link to post Share on other sites
Posted 17 Nov 2016 That is unnecessary. Reverse the two wires, and -10 to 0V becomes 0 to +10V. Share this post Link to post Share on other sites
Posted 18 Nov 2016 Hi you mean i shold connect positive analog output of plc to my negative terminal of the circuit ? in that case polarity got reverse or i will get actual negative potencial? Share this post Link to post Share on other sites
Posted 18 Nov 2016 general answer should be.... it depends. reversing wires will work a treat if analog I/Os are isolated but that is often not the case. another option is to use signal conditioner - that could be commercial unit as many made by companies like weidmueller etc. for inputs it this could also be simple voltage divider and a voltage reference, then you could use standard analog cards for -10..+10V range and forget the positive side of the range, but... what are devices that use negative range? Share this post Link to post Share on other sites
Posted 26 Nov 2016 Hi, Thank you for your reply, In last post you have mentioned that "standard analog cards for -10..+10V range" Can you suggest me that cards, I am unable to find PLC with this ranke except Siemens. One more thing, i need negative voltage doubler IC. Timer555IC works only on positive volt. Is there any SSR in which i provide 0 to -10v as control part and it provides proportional output between 0 to -20v? Thank You, Dipen Share this post Link to post Share on other sites
Posted 28 Nov 2016 Allen-Bradley has several Analog modules that support +/-10V for analog inputs. I'm online right now with a system that has these, all of which support +/-10V inputs: 1794-IE12 (Flex/IO) 1769-IF4 (CompactLogix) 1756-IF8 (ControlLogix) Look also at the Point I/O system. Share this post Link to post Share on other sites
Posted 28 Nov 2016 On 26.11.2016 at 2:38 PM, Dipen said: In last post you have mentioned that "standard analog cards for -10..+10V range" Can you suggest me that cards, I am unable to find PLC with this ranke except Siemens. You should specify what PLC brand and series you are using or want to use (preferred brand?). As far as I know most major brands have it. And if you want help to select a brand you'll need to specify what kind of application you are going to use it for, how many IOs are we talking about and so on. It's a bit like fumbling in the dark when you just say you want to have a PLC with 0 to -10V analog function... On 26.11.2016 at 2:38 PM, Dipen said: Is there any SSR in which i provide 0 to -10v as control part You want the control signal to the SSR to be 0 to -10VDC? If so just use the PLC to convert between 0 to -10V -> 0 to +10V to get a positive "normal" input to the SSR. On 26.11.2016 at 2:38 PM, Dipen said: it provides proportional output between 0 to -20v? What do you mean? You want the SSR to feed 0 to -20V output? Proportional SSR's don't feed anything as far as I know, they can only feed the actual load input voltage so it depends on what you put on the load input clamp for the SSR. Share this post Link to post Share on other sites
Posted 28 Nov 2016 2 hours ago, Joe E. said: Allen-Bradley has several Analog modules that support +/-10V for analog inputs. I'm online right now with a system that has these, all of which support +/-10V inputs: 1794-IE12 (Flex/IO) 1769-IF4 (CompactLogix) 1756-IF8 (ControlLogix) Look also at the Point I/O system. Those product families also have corresponding output modules that support +/-10V. Their new CompactLogix line also supports +/-10V I/O modules: http://ab.rockwellautomation.com/Programmable-Controllers/CompactLogix-5380-Controllers Share this post Link to post Share on other sites
