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About john_s

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  1. Keith, That makes perfect sense - just wanted to be sure when working with 120VAC inputs. Thanks, John
  2. Thanks Joe, In IO-DI8ACH they say that there's galvanic isolation between channels. Just to clarify it I have 2 questions: 1 - Since inputs are isolated - can I use separate L-phases and mix different L and N input signal lines in the same unit? 2 - In case of using a single phase - does that imply that I have to use jumper cables to tie all separate N inputs together?
  3. I guess a very generic question. My signal lines are 120VAC yet V350 comes with 24VDC inputs. What do you use / recommend to use in such situation?
  4. Joe/Simon, Fair enough - thank you. Is there a sample program on this or older forum that shows how to read, store and display a 4-20mA input in 12-bit resolution? I guess I ask here first before doing some convoluted search...
  5. Thanks Joe, I'll read through and try to understand the details of ALL that you suggested. This will be my very first attempt in programming the PLC using Unitronics tools so expect plenty of ooops... I only had my hands on V350 demo unit some time ago, and now is the time to be serious about my application. Regards, John
  6. So it's slightly less than 12-bits .. Instead of 16/4096 it is 20/4096 [mA/digit] resolution. I guess it's just a bit weird :-) Does it apply to ALL units and expansion modules?
  7. Simon, Thanks for the suggestions. I need to stay as close to ALL-IN-ONE unit unless I expand the number of A/D inputs. However, I am still a bit lost with the description of 4-20mA inputs as found in their docs. For example in V-350-35-TRA22 it says... "... Normal mode Resolution, except 4-20mA 14-bit (16384 units) Resolution, at 4-20mA 3277 to 16383 (13107 units) Conversion time 100mS minimum per channel. See Note 4 Fast mode Resolution, except 4-20mA 12-bit (4096 units) Resolution, at 4-20mA 819 to 4095 (3277 units)..." What are those magic numbers 3277 to 16383 (13107 units) and 819 to 4095 (3277 units) ? Is it 12-bit or 11.5 or ...?
  8. I focus on V350 to start with - yet the requirement is for 12-bit resolution. To my knowledge it has is 10-bit A2D only - can I improve it somehow by adding an external 12-bit A2D?
  9. This project requires 12-bit resolution when sampling the 4-20mA Inputs. However, the V-350 has a 10-bit converter ... What is a recommended way to increase it from 10-bit to 12-bits? Perhaps a different model or some external A/D Input module...? Any suggestions? Regards, John
  10. Here's my very 1st post and a question.. This project requires to read, store and display 4 current loop inputs (4 to 20mA). The data needs to be kept and displayed in table format; where Format = Date + MAX_val(day) + MIN_val(day). The other requirement is to easy read and scroll through those historical MAX and MIN values using some sort of UP and DOWN scroll buttons or a toggle switch. I'd appreciate any feedback and hardware suggestions. Regards, John
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