×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!
  • Students Click Here

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Jobs

cause effect question ("not open" and "close" difference)

cause effect question ("not open" and "close" difference)

cause effect question ("not open" and "close" difference)

(OP)
There is Low pressure hopper (above), and high pressure hopper (below), with their XV-00A(loading inlet valve), XV-00B (vent valve).

As start of the transfer, open XV-00A to allow particle to enter the low pressure hopper, then transport gas vent to collection header.

And, XV-00C, XV-00D are  transfer valves from LP hopper to HP hopper.

Could you please explain why ZSO-00C, ZSO-00D is described as "not open" instead of close when permissive action required (attached in the post)?

could you please help me out?

Thank you for your help.

RE: cause effect question ("not open" and "close" difference)

The valve has limit switches set to switch when the actuator moves through the full range of travel.  "Not open" probably means that neither the full open or full closed switches are closed.  This in turn implies that the valve is somewhere in the middle, or stuck not quite closed due to material on the seat, or the switches aren't set, or the wiring not done, or the point on the DCS/PLC not defined to the input...

While 'not open' is arguably the same as 'not closed' in a two switch scenario, the 'not open' label would be applied according to the fail safe or operator interest.

RE: cause effect question ("not open" and "close" difference)

'Not Open' is possibly a 'b' contact on the 'open' limit switch, with NOT being the logical operator to invert the signal. Depends on who wrote the datasheet.
  

----------------------------------
  
If we learn from our mistakes I'm getting a great education!
 

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members!


Resources