Electric Brewing Supply 30A BCS Giveaway!


Home Brew Forums > Home Brewing Beer > Brew Science > pH Meter - Milwaukee MW101 vs MW102
Reply
 
LinkBack Thread Tools
Old 12-19-2013, 04:08 PM   #21
Wynne-R
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2009
Location: Texas
Posts: 901
Liked 97 Times on 63 Posts
Likes Given: 77

Default

Digital vs Analog is ridiculous. To say digital is better is just as dumb as saying analog is better. Most systems these days are hybrids.

I thought the question was MW101 vs MW102. As I said in post 12, “If you want to juggle two probes and pay an extra $40, have a good time.” The 102 accuracy is rated at .01 , while the 101 is rated a still impressive .02. I prefer the simpler design of the 101 compared to the added cost and complexity of the 102.

For the record, I have considerable experience with measurement systems both analog and digital. I understand how they work. I am not a Luddite. Other than that I agree with most of what AJ said.

__________________
Wynne-R is offline
 
Reply With Quote Quick reply to this message
Old 12-19-2013, 07:10 PM   #22
ajdelange
Senior Member
HBT_SUPPORTER.png
Feedback Score: 0 reviews
Recipes 
 
Join Date: Aug 2010
Location: McLean/Ogden, Virginia/Quebec
Posts: 6,130
Liked 613 Times on 506 Posts
Likes Given: 19

Default

For fun lets design 2 pH meters: one digital and one analogue

Digital meter:

(2) LMC6001 op amps ($8 each) in instrumentation-amp config for > E14 Ω input impedance (1 gives E12)
(1) Atmel AT168 microcontroller ($4)
(1) Suitable LCD display
(1) Power supply
(2) Pushbuttons for mode control, buffer selection...
(1) Op amp for RTD (XTR105 $6 - this is for 4-20 loops but there is probably a similar part with voltage output)

Analog meter:

(2) LMC6001 op amps ($8 each) in instrumentation-amp config for > E14 Ω input impedance (1 gives E12)
(1) Atmel AT168 microcontroller ($4)
(1) Suitable LCD display
(1) Power supply
(3) Potentiometers (gain, offset, temp compensation)
(1) Op amp for gain control
(1) Reference voltage source for offset.

So you can see where the additional complexity lies.

Keep in mind that the firmware for the analog meter is much simpler than the firmware for the digital one.

Though it should go without saying I have not done a complete design here nor breadboarded nor tested either of these. This is what I was able to come up with in about 15 minutes looking at chip makers' web sites.

__________________
ajdelange is offline
 
Reply With Quote Quick reply to this message
Reply



Quick Reply
Message:
Options
Thread Tools


Similar Threads
Thread Thread Starter Forum Replies Last Post
Alabama Milwaukee MW 102 PH Meter dford For Sale 2 10-31-2013 09:51 PM
Mw102 ph meter Czm For Sale 4 07-26-2013 02:07 PM
For Sale - Milwaukee Mw101 ph meter BNIB w/ all solutions Rad-Rabbit For Sale 2 01-08-2013 09:08 PM
Mke MW101 temp setting. adam01 Equipment/Sanitation 4 09-30-2012 02:15 AM
Milwaukee pH56 meter -62.99 Steelers77 Sponsor Showcase 0 10-28-2011 03:24 PM