You are not registered yet. Please click here to register!

plc storereviewsdownloads
This board is for PLC Related Q&A ONLY. Please DON'T use it for advertising, etc.
Try our online PLC Simulator- FREE.  Click here now to try it.

---------->>>>>Get FREE PLC Programming Tips

New Here? Please read this important info!!!

Go Back - Interactive Q & A > - Interactive Q & A > LIVE PLC Questions And Answers

PLC training tools sale

Thread Tools Display Modes
Old October 14th, 2011, 07:27 AM   #1
United States

agarb is offline
Join Date: May 2006
Location: USA
Posts: 277
Local/Off/Remote Selector Switches & Continuous Processes

Is an Local-Off-Remote switch just another name for a Hand-Off-Auto switch?

If so, I assume that a LOR switch would be implemented similar to the HOA switch in the attached pdf.

I am normally used to working on stand-alone machinery that performs a specific sequence and then repeats after being unloaded and loaded by an operator.

Now consider some machinery running a continuous process. There are approximately 10 motors which all must be running and remain running for the process to continue. Why would a customer specify that they want LOR switches for all the motors? It seems to me that there would be the danger of somebody walking by and turning off one motor thus disrupting the entire process. The process in question is not trivial to start up, especially if not "emptied" out properly before stopping.

Thoughts? How are LOR switches implemented in your facility?
Attached Files
File Type: pdf Siemens Bucket.PDF (164.1 KB, 56 views)
  Reply With Quote
Old October 14th, 2011, 09:06 AM   #2
Lifetime Supporting Member
United States

Lancie1 is offline
Lancie1's Avatar
Join Date: Jul 2003
Location: Alabama
Posts: 10,002
Why would a customer specify that they want LOR switches for all the motors?
Your customer could want Local switches: 1. To test the motor and what it does without running the entire system, 2. To allow manual operation when the Remote device fails.

Yes, there is a danger that someone could switch to Local when he should not. However, without the Local mode, there is a danger that your Remote device will fail and the owner will be left with nothing. What this says (one way or another) is that he does not completely trust what you are using and doing.

I always request Local-Off-Remote or Hand-Off-Auto switches everywhere that is appropriate, because I, too, am not a trusting guy.

Last edited by Lancie1; October 14th, 2011 at 09:09 AM.
  Reply With Quote
Jump to Live PLC Question and Answer Forum


Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
Thread Tools
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump

Similar Topics
Thread Thread Starter Forum Replies Last Post
ControlLogix L-55 Scan Problem MorphuisOGrady LIVE PLC Questions And Answers 19 July 15th, 2009 08:34 AM
Continuous weighing with a PID control. pietervdb LIVE PLC Questions And Answers 26 April 10th, 2008 12:05 PM
Progressive Dies, Mechanical Presses, Continuous Cycles, etc. Tharon LIVE PLC Questions And Answers 9 March 6th, 2007 09:48 PM

All times are GMT -5. The time now is 10:46 AM.