Using Inexpensive Relays for Mixed Voltage Systems

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Gary Campbell
Posts: 155
Joined: Sat Nov 18, 2017 2:32 pm
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System Serial Number: C8FD19D3C3E1-1109170238
Location: Marquette, MI

Using Inexpensive Relays for Mixed Voltage Systems

Post by Gary Campbell » Fri Feb 09, 2018 6:30 pm

Every now and then, and maybe even more often that that, it appears that Acorn systems are using dual voltage (24vdc and 5vdc) to provide logic and power to various brands of drives. My "Acorn Project" is no different. The Acorn control board is native 24vdc and even tho the Leadshine drives I have selected can use 5-24vdc for control signals, the alarms are 5vdc max.

That means that no matter what voltage I use for the signals, my alarms will be required to use 5vdc, which will not work with the Acorn. There are a number of opto isolation devices, chips and circuits that could be used, but since I had some inexpensive relays on hand I decided to use them and this video will show those who may need to do something similar, how to do it.

https://youtu.be/kN-EzRbRa_k
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ScotY
Posts: 344
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Location: Honolulu, HI

Re: Using Inexpensive Relays for Mixed Voltage Systems

Post by ScotY » Sat Feb 10, 2018 2:35 am

Hi Gary,
Enjoyed the video...thanks for doing that. I’m not sure yet but perhaps I may need to do this at some point. Might you be able to post the specifics on what relay boards to use here for reference?

Gary Campbell
Posts: 155
Joined: Sat Nov 18, 2017 2:32 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: C8FD19D3C3E1-1109170238
Location: Marquette, MI

Re: Using Inexpensive Relays for Mixed Voltage Systems

Post by Gary Campbell » Sat Feb 10, 2018 9:37 am

Scot..
I would rather not post an eBay link as they often last only a few days or weeks. When I buy these I buy a bunch, and accept overseas shipping times as there is no emergency. So I don't know if the one I used is 2 months or 2 years in my bin. If I have an immediate need I will order from Factorymation: http://www.factorymation.com/General_Pu ... _Series_SB

The ones that Marty posted in his video will work fine, assuming you match your requirements.

For the generic cheapos: do what I do: Search eBay for: "5v relay module low trigger"

Of course you will have to enter the appropriate voltage and high or low for your case. Note: there are now a number of vendors (some in the US) showing these (2,4,8) relay modules that are selectable for high or low trigger voltage. I have just ordered a half dozen of them.
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ScotY
Posts: 344
Joined: Sat Sep 23, 2017 7:57 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: none
Location: Honolulu, HI

Re: Using Inexpensive Relays for Mixed Voltage Systems

Post by ScotY » Sat Feb 10, 2018 2:21 pm

Hi Gary,

Thanks! Yes, agreed on eBay links but your search description is exactly what we need here.

Marty calls them NPN and PNP, if I remember correctly. NPN is what you call low trigger and PNP is high?

I ordered one of the types Marty recommended just to have on hand but I think it’s a 24v version so I should probably order a 5v to have on hand.

Gary Campbell
Posts: 155
Joined: Sat Nov 18, 2017 2:32 pm
Acorn CNC Controller: Yes
Allin1DC CNC Controller: No
Oak CNC controller: No
MPU11 & GPIO4D -w/ 3rd Party Drives: No
DC3IOB: No
CNC11: No
CPU10 or CPU7: No
System Serial Number: C8FD19D3C3E1-1109170238
Location: Marquette, MI

Re: Using Inexpensive Relays for Mixed Voltage Systems

Post by Gary Campbell » Sat Feb 10, 2018 2:34 pm

Scot...
Yes. NPN = Low Trigger = Sink PNP = High Trigger = Source
GCnC Control
CNC Control & Retrofits
https://www.youtube.com/user/Islaww1/videos

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