EATON
HFX Product Family Installation and Operation Manual E-ELCL-II002-E2 July 2019
27
HFX Product Family
16.0
ANALOG INPUT CIRCUIT (PASSIVE
REPRESENTATION)
The options are as follows:
Manual Config mode:
•
Pull-up configurable
•
Pull-down configurable
•
Shunt configurable
Note: The manual mode is useful when connecting binary
sensors. If you have a sensor that is switching ground to the
input, you should enable the pull-up and set the rising threshold
appropriately for the sensor (normally 2500 mV). If you have a
sensor that is switching battery voltage, you should enable the
pull-down and set the falling threshold appropriately for the
sensor (normally less than half the battery voltage). Make sure
to take into consideration the effect of hysteresis i.e. have some
margin between rising and falling thresholds.
0-5 V mode (ratiometric):
•
Pull-down forced off
•
Pull-up configurable
•
Shunt configurable
0-5 V mode (absolute):
•
Pull-down forced off
•
Pull-up configurable
•
Shunt configurable
0-10 V and 0-34 V mode:
•
Pull-down forced on
•
Pull-up configurable
•
Shunt configurable
0-22 mA mode:
•
Pull-up forced off
•
Pull-down forced off
•
Shunt forced on
Thermistor raw mode
(output the 10 kΩ to 50 kΩ value):
•
Pull-up forced on
•
Pull-down forced off
•
Shunt forced off
Thermistor #1 & #2 mode
(output the temperature value):
•
Pull-up forced on
•
Pull-down forced off
•
Shunt forced off
The status of the Pull-up, Pull-down, and Shunt
are displayed for convenience. In Manual Config, the
programmer has complete control to alter
these values.
Each of the analog modes offers a user adjustable
filter. The purpose of this is to smooth an input
signal and/or limit how quickly it is changing. The
filter is a digital approximation of a first order series
RC network (low pass filter). The adjustable time
constant is equivalent to the product of R*C in a
conventional RC filter. The input should follow the
following curve approximately (+/- 10%): 63% of the
new step-response value after 1 time constant - after
2 time constants you will get to 86% and after 3 you
will get 98%.
The digital mode features adjustable rising and falling
threshold levels. This is intended to offer additional
flexibility in input device selection. There is also
a debounce associated with each input. It is only
intended for digital use (mainly to prevent inadvertent
input triggering from multiple mechanical contact
closures). The debounce has a user configurable time
period. Each digital input can function with either
Low Side or High Side input types.
Additionally, each of the modes offer a user
configurable under-range and over-range limit
coupled to respective fault bits.
Note 1: There is an overcurrent fault that triggers when the input
exceeds approximately 23.5 mA for 25 ms in 0 – 22 mA mode.
Note 2: Ratiometric mode compensates for the measured
regulated output voltage variance and normalizes the input value
relative to 5 volt sensor supply.
