cedax Posted October 26, 2018 Report Share Posted October 26, 2018 Hi everyone, On my EXD16A3TO16 I need more inputs. It' possible to use Analogs inputs? if I connect a 2.7K resistor between 24v and the input it can work? Quote Link to comment Share on other sites More sharing options...
MVP 2022 Ausman Posted October 26, 2018 MVP 2022 Report Share Posted October 26, 2018 A single analog input can be used successfully to implement multiple switch inputs if you need to go that far. Depending on different switch positions, a different resistance is applied resulting in different analogue readings. You have to map this out carefully if doing this approach, so that every switch combination gives you a distinct "zone" of an input, and you then use a range reading in the plc logic. If you use a single value you will likely run into problems. In setting this sort of thing up, I always use a multi-turn 10K trimpot (or a number of them) to initially find optimum resistances for what I want. Theory doesn't necessarily work out correctly due to drift, component tolerances etc. cheers, Aus Quote Link to comment Share on other sites More sharing options...
MVP 2022 Joe Tauser Posted October 26, 2018 MVP 2022 Report Share Posted October 26, 2018 Or you could just buy an IO-DI16 and tack it on. Joe T. Quote Link to comment Share on other sites More sharing options...
MVP 2022 Flex727 Posted October 27, 2018 MVP 2022 Report Share Posted October 27, 2018 Or even a IO-DI8-RO4, which might be just a smidgen cheaper. Quote Link to comment Share on other sites More sharing options...
Don2015 Posted November 30, 2018 Report Share Posted November 30, 2018 One time I needed more Inputs but did not have room in the enclosure for 2 more modules, so I took 5 inputs and treated them as binary, depending on which inputs were on I knew which switch was pushed, so I got 25 inputs from just 5 inputs, I also used 5 small relay cards at 4 relays per card . Then the rest was just in programming! Don2015 Quote Link to comment Share on other sites More sharing options...
Isakovic Posted December 1, 2018 Report Share Posted December 1, 2018 13 hours ago, Don2015 said: One time I needed more Inputs but did not have room in the enclosure for 2 more modules, so I took 5 inputs and treated them as binary, depending on which inputs were on I knew which switch was pushed, so I got 25 inputs from just 5 inputs, I also used 5 small relay cards at 4 relays per card . Then the rest was just in programming! I had a similar situation but with outputs. Each output controlled two valves, but one valve was getting negative from supply from NC contact of reley, and other one was getting it from NO contact, so that relay altered which group will be activated. So I got 14 valves from 8 outputs. Crude and patchy solution, but it was some pneumatic cleaner so nothing critical. Quote Link to comment Share on other sites More sharing options...
MVP 2022 kratmel Posted December 1, 2018 MVP 2022 Report Share Posted December 1, 2018 To solve a problem similar to yours, I used 1 input and alternatively connected various sources to it for analysis. In my case, there were a few free relay outputs and I used them to connect various alarm signals. This option is good for slow processes. Therefore, having analyzed the problem I have created a program in which the high priority inputs are being surveyed more often than others. Quote Link to comment Share on other sites More sharing options...
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