Hysteresis and Threshold
Threshold and hysteresis work together to establish the ON and OFF points of an analog input. The threshold
defines a trigger point or reporting threshold (ON point) for a sensor input. When the input value is higher than the
threshold, the input is ON. Hysteresis defines how far below the threshold the analog input is required to be before
the input is considered OFF. A typical hysteresis value is 10% to 20% of the unit’s range.
In the example shown, the input is considered on at 15 mA. To consider the input off at 13 mA, set the hysteresis to
2 mA. The input will be considered off when the value is 2 mA less than the threshold.
Threshold
ON point
Time
Input V
alue
Input
Hysteresis
OFF point
Input Type
Program the universal inputs to accept input types NPN, PNP, 10k thermistor, 0 to 10 V, 0 to 20 mA, or
potentiometer. The default setting is 8: NPN raw fast. To set the input type, write the following values to the Input
Type Modbus registers.
0 = NPN
1 = PNP
2 = 0 to 20 mA
3 = 0 to 10 V DC
4 = 10k Thermistor
5 = Potentiometer Sense (DXM150 only)
6 = Not used
7 = Bridge
8 = NPN Raw Fast (default)
Temperature °C/°F
Set to 1 to represent temperature units in degrees Fahrenheit, and set to 0 (default) to represent temperature units in
degrees Celsius.
9.2.10 Modbus Configuration Registers for Power
To monitor the input power characteristics of the DXM, read the following power Modbus registers. The on-board thermistor
is not calibrated, but can be used as a non-precision temperature input.
Table 52: Configuration registers for power
Modbus Register
Description
6071
Battery backup charging algorithm.
0 = Battery is recharged from a solar panel
1 = Battery is recharged from 12 to 30 V DC (default)
6081
Battery voltage (mV). If no battery is present, the value in this register is less than 5 V. If the value in this register is greater than
the incoming voltage register, the battery is powering the system.
6082
Battery charging current (mA). The charging configuration charges the battery when the incoming voltage register value is greater
than the battery voltage register value. This registers shows the charging current in milliamps.
6083
Incoming supply voltage (mV) (solar or power supply). The incoming power can be from a solar panel or from a power supply.
The battery is charging when the incoming voltage register value is greater than the battery voltage register value. The battery is
powering the system when the incoming voltage register value is less than the battery voltage register value.
6084
On-board thermistor temperature (⁰C). A thermistor measures the temperature of the solar controller board and its surrounding
area and uses the temperature as part of the battery charge calculations. This register stores the thermistor reading in tenths of
degrees C. This is not a calibrated input: divide by 10 to calculate the temperature in degrees C. For calibrated temperature
inputs, define one of the universal inputs as a temperature input.
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DXM150 and 1500-Bx Wireless Controllers
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