Installation 2-3
Series
505 High Speed Counter
and Encoder Module User
’
s Manual
2.1.4
General
W
iring
The count, inhibit, and unfiltered reset inputs are high-speed inputs which
Considerations
may respond to noise present on the lines. T
o avoid problems, follow these
guidelines when installing the HSC module.
D
Use the shortest possible wires.
DA
void placing signal wires parallel to high-energy wires. If the two
must meet, cross them at right angles.
DA
void bending the wire into sharp angles.
D
Use wireways for wire routing.
D
When using shielded wires, ground them only at the source end for
better noise immunity
.
D
Place wires so that they don’t interfere with existing wiring.
D
Label the wires.
In some installations when both the HSC and TI505-49XX series of relay
modules are used, false counts may be induced when switching high
voltage in the relay module, (voltage > 40 V
rms). This is the result of
internal arcing of the relay contacts.
If you encounter this problem, place a snubber consisting of a 47 ohm 1/4
watt resistor and a 0.022
Fd capacitor across the relay contact terminals
on the terminal block. Snubbers were not included in the relay modules in
order to meet the need for lower current leakage in many applications.
:
Snubber components must be UL
r
component r
ecognized
and/or CSA Certified for use acr
oss the rated voltage being switched
by the r
elay module.