22mm keyed potentiometer - PLCS.net

lesmar96 · February 6th, 2020, 05:03 PM

I have a customer who has requested a keyed 22MM potentiometer on his enclosure to provide speed reference for the VFD.

Basically to prevent unauthorized folks to adjust the speed. My common suppliers do not seem to offer this. Have you seen or used any? Any suggestions?

GaryS · February 6th, 2020, 05:12 PM

I have ever even heard of a keyed pot. Pots are not used much anymore now that most thigs have gone digital.
You may try to use a key activated 3 position spring return to center selector switch and use the ram up / down function of the vfd
it would meet the their needs and simple to find and setup.

lesmar96 · February 6th, 2020, 05:16 PM

I had thought of that as an option, but first I wanted to explore what he asked for first.

James Mcquade · February 6th, 2020, 05:49 PM

can you put a keyed switch in vfd for permission?
can you put a locked cover over the speed pot?
I have used keyed enclosure door handles before.

just some ideas.
James

JERA · February 7th, 2020, 04:02 AM

Schneider Electric have 22MM potentiometers:

https://www.se.com/us/en/product-ran...849+2427091364

rdrast · February 7th, 2020, 04:21 AM

Put a normal pot in a lockable box.

JesperMP · February 7th, 2020, 06:43 AM

Something like this maybe:
https://www.amazon.com/Master-Lock-S.../dp/B00BD9PFHA

Aabeck · February 7th, 2020, 07:10 AM

That Amazon box has a nice look, but from my experience it would be smashed within 10 to 15 minutes. Plus, from experience with waitresses and locked thermostat covers, a knife would slide in the edges and be able to turn the pot - but not a fine control so probably too much.

I would put a regular lockable plastic enclosure.

lesmar96 · February 7th, 2020, 07:34 AM

He does want the pot on the outside of the enclosure, but just prevent unauthorized people from using it.

Have any suggestions for a good 22MM lockable cover?

77nomad · February 7th, 2020, 07:41 AM

As stated, in my 22 years on the shop floor. It would be smashed in days. That being said, if it's not to be messed with. Why not leave it in the panel? Lock the panel? Or talk them into an HMI and password protect it.

Steve Bailey · February 7th, 2020, 08:14 AM

Keyed switch on the control panel next to the pot. Pot signal wired to a PLC analog input. PLC analog output is actual speed reference to the drive. Logic in the PLC program to transfer the pot signal to the reference when the keyswitch is on, otherwise leave the reference unchanged. Perhaps an illuminated keyswitch to warn the operator of a large difference between the pot setting and the actual reference due to pot twiddling without the keyswitch. That's complicated enough to maybe convince the customer that its easier to accomplish what they want (speed changes only by authorized people) using an HMI.

Aabeck · February 7th, 2020, 08:31 AM

Automation Direct

Padlockable, 6x6 box, $75

lesmar96 · February 7th, 2020, 03:46 PM

Quote:

Originally Posted by Steve Bailey

Keyed switch on the control panel next to the pot. Pot signal wired to a PLC analog input. PLC analog output is actual speed reference to the drive. Logic in the PLC program to transfer the pot signal to the reference when the keyswitch is on, otherwise leave the reference unchanged. Perhaps an illuminated keyswitch to warn the operator of a large difference between the pot setting and the actual reference due to pot twiddling without the keyswitch. That's complicated enough to maybe convince the customer that its easier to accomplish what they want (speed changes only by authorized people) using an HMI.

I had thought of something similar to this. They would like to be able to adjust the speed with gloves on, thus we are sticking with the pot and not going HMI all together. They will have to decide between all their wants and their needs.

Thanks for your help again!

Aabeck · February 7th, 2020, 04:12 PM

Quote:

Originally Posted by lesmar96

They would like to be able to adjust the speed with gloves on

Then how would they get a key in the lock?

Suggest the key switch method to adjust as mentioned, but instead of a key switch use a RFID identification stick.

lesmar96 · February 7th, 2020, 04:16 PM

Quote:

Originally Posted by Aabeck

Then how would they get a key in the lock?

Suggest the key switch method to adjust as mentioned, but instead of a key switch use a RFID identification stick.

From my experience a keyed selector switch would be workable with gloves on, although the RFID idea is not a bad one

February 6th, 2020, 05:03 PM	#1
lesmar96 Lifetime Supporting Member Join Date: May 2017 Location: PA Posts: 462	22mm keyed potentiometer I have a customer who has requested a keyed 22MM potentiometer on his enclosure to provide speed reference for the VFD. Basically to prevent unauthorized folks to adjust the speed. My common suppliers do not seem to offer this. Have you seen or used any? Any suggestions? __________________ Whatever you are, be a good one.

February 6th, 2020, 05:16 PM	#3
lesmar96 Lifetime Supporting Member Join Date: May 2017 Location: PA Posts: 462	I had thought of that as an option, but first I wanted to explore what he asked for first. __________________ Whatever you are, be a good one.

February 7th, 2020, 04:21 AM	#6
rdrast Lifetime Supporting Member Join Date: Apr 2003 Location: South Carolina Lowcountry Posts: 5,483	Put a normal pot in a lockable box. __________________ ------------------------------------ How to ask questions the SMART Way! Look First, Ask Second!

February 7th, 2020, 06:43 AM	#7
JesperMP Lifetime Supporting Member + Moderator Join Date: Feb 2003 Location: Copenhagen. Posts: 14,520	Something like this maybe: https://www.amazon.com/Master-Lock-S.../dp/B00BD9PFHA __________________ Jesper See my profile interests for Q&A

February 7th, 2020, 07:10 AM	#8
Aabeck Member Join Date: Feb 2013 Location: Detroit Posts: 1,860	That Amazon box has a nice look, but from my experience it would be smashed within 10 to 15 minutes. Plus, from experience with waitresses and locked thermostat covers, a knife would slide in the edges and be able to turn the pot - but not a fine control so probably too much. I would put a regular lockable plastic enclosure. __________________ Never underestimate the quality of idiots that will be running your machines http://aabeck.com



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.*

February 6th, 2020, 05:12 PM	#2
GaryS Member Join Date: Aug 2003 Location: Lancaster Pa. Posts: 1,470	I have ever even heard of a keyed pot. Pots are not used much anymore now that most thigs have gone digital. You may try to use a key activated 3 position spring return to center selector switch and use the ram up / down function of the vfd it would meet the their needs and simple to find and setup.

February 6th, 2020, 05:49 PM	#4
James Mcquade Member Join Date: Oct 2007 Location: Tennessee Posts: 2,939	can you put a keyed switch in vfd for permission? can you put a locked cover over the speed pot? I have used keyed enclosure door handles before. just some ideas. James

February 7th, 2020, 04:02 AM	#5
JERA Member Join Date: Feb 2006 Location: Copenhagen Posts: 304	Schneider Electric have 22MM potentiometers: https://www.se.com/us/en/product-ran...849+2427091364

February 7th, 2020, 07:34 AM	#9
lesmar96 Lifetime Supporting Member Join Date: May 2017 Location: PA Posts: 462	He does want the pot on the outside of the enclosure, but just prevent unauthorized people from using it. Have any suggestions for a good 22MM lockable cover? __________________ Whatever you are, be a good one.

February 7th, 2020, 07:41 AM	#10
77nomad Member Join Date: Jan 2017 Location: Mi. Posts: 71	As stated, in my 22 years on the shop floor. It would be smashed in days. That being said, if it's not to be messed with. Why not leave it in the panel? Lock the panel? Or talk them into an HMI and password protect it.

February 7th, 2020, 08:14 AM	#11
Steve Bailey Lifetime Supporting Member + Moderator Join Date: Apr 2002 Location: The boondocks of Western Massachusetts USA Posts: 7,363	Keyed switch on the control panel next to the pot. Pot signal wired to a PLC analog input. PLC analog output is actual speed reference to the drive. Logic in the PLC program to transfer the pot signal to the reference when the keyswitch is on, otherwise leave the reference unchanged. Perhaps an illuminated keyswitch to warn the operator of a large difference between the pot setting and the actual reference due to pot twiddling without the keyswitch. That's complicated enough to maybe convince the customer that its easier to accomplish what they want (speed changes only by authorized people) using an HMI.

February 7th, 2020, 08:31 AM	#12
Aabeck Member Join Date: Feb 2013 Location: Detroit Posts: 1,860	Automation Direct Padlockable, 6x6 box, $75 __________________ Never underestimate the quality of idiots that will be running your machines http://aabeck.com

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

Thread Tools
Show Printable Version Email this Page
Display Modes
Linear Mode Switch to Hybrid Mode Switch to Threaded Mode

Similar Topics
Thread	Thread Starter	Forum	Replies	Last Post
OMRON E5AN-H setting up valve with potentiometer	maxsoft	LIVE PLC Questions And Answers	5	July 20th, 2017 12:29 PM
4-20 mA Potentiometer	strebej	LIVE PLC Questions And Answers	18	March 12th, 2011 09:00 PM
Potentiometer Input Proportioanl Controller for DC...	Eric Nelson	LIVE PLC Questions And Answers	7	January 12th, 2011 09:15 AM
PID control of motor drive considering the diameter and an external Potentiometer	rajesh_gklm	LIVE PLC Questions And Answers	2	January 16th, 2010 12:19 AM
Analog Input With Potentiometer HELP!!	zmanvortex	LIVE PLC Questions And Answers	26	May 11th, 2006 09:14 AM