Welcome to EDAboard.com

Welcome to our site! EDAboard.com is an international Electronics Discussion Forum focused on EDA software, circuits, schematics, books, theory, papers, asic, pld, 8051, DSP, Network, RF, Analog Design, PCB, Service Manuals... and a whole lot more! To participate you need to register. Registration is free. Click here to register now.

Measureing Fan Tacho Signal

Status
Not open for further replies.

SparkyChris1976

Newbie level 4
Joined
Apr 19, 2012
Messages
6
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Portsmouth, UK
Activity points
1,326
Hi All,

I want to control the speed of a fan by measuring the tacho signal in the feedbac loop.
I am using a micro-controller to implement the circuit, and plan to use the micro's timers to 'time'
the tacho signal and calculate the speed.

My question is, is it ok to just stuff the tacho signal into the micro or should I apply any kind of filtering?
Bear in ind I probably need clean sharp edges for the timers to catch the edges realiably.

Any thoughts appriciated.


Chris
 

HTA

Advanced Member level 1
Joined
Nov 17, 2011
Messages
445
Helped
108
Reputation
216
Reaction score
104
Trophy points
1,323
Activity points
3,925
Hi Chris,

what kind of tacho signal you get from the fan motor? Usually the fan datasheet tells you how to interface to the micro. If it is an open collector output you need a pull-up on the micro input. If you have long lines to the micro for the tacho signal you might need a buffer. For interfacing the micro to the outside world you might find this application useful: https://ichaus.biz/mcu_interface .

Enjoy your design work!
 

SparkyChris1976

Newbie level 4
Joined
Apr 19, 2012
Messages
6
Helped
0
Reputation
0
Reaction score
0
Trophy points
1,281
Location
Portsmouth, UK
Activity points
1,326
Hi Chris,

what kind of tacho signal you get from the fan motor? Usually the fan datasheet tells you how to interface to the micro. If it is an open collector output you need a pull-up on the micro input. If you have long lines to the micro for the tacho signal you might need a buffer. For interfacing the micro to the outside world you might find this application useful: https://ichaus.biz/mcu_interface .
Enjoy your design work!

Thanks HTA,

I have not decided on a particular fan just yet. That would be good if the fan data sheet gives some info on how to interface to the tachometer. At this point I was just wondering if tachometers bring any noise issues with them, that I should be aware of.

Thanks for the link, that's really useful.

Cheers,
Chris
 

Status
Not open for further replies.

Similar threads

Part and Inventory Search

Welcome to EDABoard.com

Sponsor

Top