Parker PHD Series - Power

20 PHD
Inputs
3.3.3. PHD50/PHD70 frequency input capabilities
The PHD50 and PHD70 have 2 frequency inputs. These inputs are also
configurable as digital inputs. The frequency inputs are ideal for use with hall-
effect type sensors.
The following table provides specifications for the frequency inputs:
Frequency Input Specifications
Item
MIN
NOM
MAX
UNIT
Input range
0
5
32
V
Negative threshold
1.545
V
Positive threshold
4.008
V
Input capacitance at pin
0.1
µF
Over-voltage
36
V
Frequency accuracy
3
%
Frequency range (see note)
0
1500
Hz
Pull-up resistor to min 4.3V, max 5V
1.2
kΩ
Pull-down resistor
26.2
kΩ
Note: Electrically signals to 0 are possible, but the software will limit the minimum
measurable frequency
3.3.3.1. DC-Coupled Frequency Input Connections
When connecting DC-coupled frequency inputs, be aware of system noise and
ground level shift.
System Noise
DC-coupled frequency inputs are more susceptible to system noise than digital
inputs.
To reduce system noise:
▪ Connect DC-coupled frequency inputs to sensors that produce signals with no
DC offset.
▪ Use the shortest possible wires when connecting DC-coupled frequency inputs
to sensors to prevent noise pickup on the sensors.
Ground Level Shift
Ground level shift affects the accuracy of DC-coupled frequency inputs. Ground
level shift refers to the difference between the system ground input (GND)
voltage, and the sensor ground voltage.