User manual

1-Wire Application Guide v1.04 Page 31 of 41
directly proportional to the current flowing through whatever wire the CT3110
current probe is clamped on to.
The CT3110 current probe is available from Midon Design.
Resistor R1 in Figure 24 can be chosen by the formula
R1 = V x 3100 / I
Where
V = 10 Volts (the maximum input to a DS2438) x 1.414 (scaled to DC) =
14.14 Volts
And
I = the maximum expected current on the circuit being measured.
As an example, if you expect to see no more than 20 Amps on a circuit, then
R = 14.14 x 3100 / 20 = 2192Ω
2192 is not a standard value resistor, so you can use a variable resistor to
achieve this value, or simply use the next closest value. In this case, that would
be a 2200 Ω resistor.
Figure 24 1-Wire Current Sensor
4.5.1 HVAC Monitor
Eric Vickery at Hobby Boards has designed a general-purpose voltage monitor,
based on the DS2450 Quad ADC, which can be used, amongst other things to
monitor your HVAC system. This sensor is compatible with TEMP08. If you are
using this device without having a wind direction sensor installed on the same