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XDI200 Manual Version 0.1
- Page 45 -
©2017 Electromotive, Inc.
Fig. G.2 1:
Sample
TPS
75
3.75
81
158 237
80
4.00
86
168 253
85
4.25
91
178 269
90
4.50
96
188 285
95
4.75
100 198 300
100
5.00
105 208 315
5.2 Throttle Position Sensor
The throttle position sensor (TPS) functions as a multi-purpose
input to the
XDI200
. The TPS is optional and is only used for
activating the Idle air motor and for data logging purposes.
TPS’s that
are compatible with the
XDI200
must be of the potentiometer
(rheostat) variety. A potentiometer has three connections: +5Volt,
Ground, and Output Signal. As the throttle is moved, the TPS output
should transition smoothly from a low voltage (approaching 0V) at idle to a high voltage
(approaching 5V) at full throttle. Switch-
type TPS’s will NOT work with a
XDI200
since they do
not output a smooth voltage transition from closed to opened throttle.
The throttle position sensor should have a resistance of roughly 10k
measured across
the +5V and Ground terminals. To determine the pin out of an unknown TPS, follow the
instructions below (you will need an ohmmeter):
1. With the TPS in the
closed throttle
position, measure the
resistance of the following three positions referenced to
Figure
G.2.1
: A-B, A-C, and B-C.
2. With the TPS in the
opened throttle
position, measure the same
three resistances. Two of the readings will have changed from
Step 1, and one of the readings will be the same.
3. The +5V and Ground terminals are from the terminal pair whose
resistance stayed the same between steps 1 and 2. The
Ground
terminal is from the pair whose resistance
increased
from Step 1 to Step 2.
Example:
Step 1.
Closed Throttle: A-B : ~500
B-C : ~9500
A-C : ~9500
Step 2.
Opened Throttle : A-B : ~9500
B-C : ~500
A-C : ~9500
Step 3:
Process of Elimination
A-
C resistance stayed the same in steps 1 & 2. Therefore, either “A” or “C” is
the Ground connection.
A-B resistance increased from ~500
to ~9500
from Step 1 to Step 2.
Therefore, “A” or “B” is the ground connection.
“A” must be the Ground
connection since “B” cannot be the ground
connection as a result of Step 1.
“C” must be the +5 Volt
connection, since “A” is not.
“B” must then be the Output Signal
.
