TT-3026L easyTrack Transceiver
Installation Manual
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4.4
C
ONNECTING A
T
ACHO GRAPH
The TT-3616T is designed to interface to tacho graph devices
with a pulse per meter output compatible with the
specification given in Table 7. A common standard is a
calibration of 4 impulses per meter, but other ratios can be
used as well (software configurable, ref. [2] section 8.16.5).
The tacho graph signal
must
be connected to AUX3.
The AUX1-AUX3 inputs are characterised by:
Parameter
Value
Remark
Input resistance
R
in
= 100 k
Allowed voltage
range
0V
V
in
12V
EMC Protection
may be harmed if
level is exceeded.
Input filter:
1
st
order low
pass, f
3dB
=416Hz
Low level voltage
V
in
< 2 V
Typical 2.5V
High level voltage
V
in
> 7 V
Typical 6.5V
Voltage hysteresis
> 3V
Typical 4V
Note: All values are referenced to GND.
Table 7 AUX1-AUX3 input characteristics
The tacho graph must be referenced to the GND
2
signal.
Possible grounding schemes are shown in Figure 14 and
Figure 15.
If the Tacho graph has a signal ground pin, the grounding
should be made as shown in Figure 14. If not, then the
grounding scheme shown in Figure 15 should be used in
order to reduce noise from other electrical installations.
2
The TT-3026L Transceiver has an isolated power supply, thus
no connection between DC- and GND is made inside the
transceiver
