UMAX030211 Version 1.0.2. Preliminary Documentation – May be subject to change
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2.1.1.
Resistive Input
The controller has one Resistive Input in the 8 pin Deutsch connector that can measure resistances
and it can be also configured to measure Digital On/Off states. The Digital On/Off state reading is
done using an ADC and comparing the conversion results to built-in thresholds.
The preferred Digital Input voltages to the Resistive Input are 0V (low) and 5V (high).
When configured as a Resistive Input, the controller uses the ADC and internal reference current
generator to measure the resistance between the Resistive Input pins.
The default resistive input measurement unit in object 7100h is kΩ.
2.1.2.
Digital Input
The Digital Input located also in the 8 pin Deutsch connector is capable of detecting Digital On/Off
states. It does not require any specific configuration, the ‘on/off’ state can be read directly from AI
Input Field/Process Value objects and from object 6000h.
The Universal Inputs can operate as digital inputs using the digital input (DI) function block. It only
becomes applicable on the input when object 6112h,
AI Operation
, is set to a digital input response.
Figure 5 – Digital Input Objects
When object 6112h is set to 10 =
Digital Input
, object 2020h
DI Pull-up/Pull-down Mode
will
determine the configuration of the internal Pull-up/Pull-down resistors. The options for object 2020h
are shown in Table 9, with the default bolded.
Value Meaning
0
Pullup/Down Disabled (high impedance input)
1
10kΩ Pullup Resistor Enabled
2
10kΩ Pulldown Resistor Enabled
Table 9 – DI Pullup/Down Options
Figure 6 shows the hysteresis on the input when switching a discrete signal. A digital input can be
switched up to +Vcc (42Vmax.)
