Calculate voltage from resistance

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Calculate voltage from resistance

Postby IDP on Fri Feb 26, 2010 6:53 am

Can anyone explain how to calculate sensor voltage based on resistance table.

I have the resistance table but need voltage taking into account the pull up and pull down resistor in M800 AT input.

Thanks in advance.
IDP
 
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Re: Calculate voltage from resistance

Postby Holmz on Sat Feb 27, 2010 1:18 pm

Either you will need to get an electronics book, or get someone knowledgeable.
A simple electronics book or physics book covers it all.

Typically you would either have:
1) A resistor between the 12v and the device "pulling up" the voltage as measured at the device's input.
or
2) The device hooked up to 12v with a resistor pulling down the output as measured at the device's output.

Perhaps attach the specs of the device's resistance characteristics.

Question - I am assuming that most people use a regulated voltage for the source????
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Re: Calculate voltage from resistance

Postby IDP on Sun Feb 28, 2010 4:21 am

Ok.

it's an M800 AT input.
1000 ohms to 5V
100 Kohms to 0V

Sensor is a PT 1000 type as below.

T (°C) R(Ohm)l
-20 924
-10 962
0 1000
10 1038
20 1076
25 1095
30 1114
40 1152
50 1190
60 1228
70 1266
80 1304
90 1342
100 1380
110 1419
120 1457
130 1495
140 1533
150 1571
160 1609
170 1647

These values work fine in ADL2 but I now need a sensor connected directly to the ECU so need the appropriate voltages.

Many thanks for any help.
IDP
 
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Re: Calculate voltage from resistance

Postby Merlin on Sun Feb 28, 2010 9:06 pm

if you can simulate the resisance you can use the read value function in the Input set screens to get the voltages

John P
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Re: Calculate voltage from resistance

Postby Polux RSV on Sun Feb 28, 2010 9:27 pm

Hare are the voltages:

T (°C) R(Ohm) V(volts)
-20 924 2.39
-10 962 2.44
0 1000 2.49
10 1038 2.53
20 1076 2.58
25 1095 2.6
30 1114 2.62
40 1152 2.66
50 1190 2.7
60 1228 2.74
70 1266 2.78
80 1304 2.81
90 1342 2.85
100 1380 2.88
110 1419 2.92
120 1457 2.95
130 1495 2.98
140 1533 3.01
150 1571 3.04
160 1609 3.06
170 1647 3.09

Angelo
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Re: Calculate voltage from resistance

Postby IDP on Sun Feb 28, 2010 11:56 pm

Thank you very much for your help.
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Joined: Wed Aug 13, 2008 11:30 pm


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