Figure 16 Digital Input Voltage Range; Table 6 Digital Input Wiring - Mircom OpenBAS-LC-NX12R Installation Manual

Any voltage that lies between 4.1 to 7.9 V can give ambiguous results and must be avoided.
See Figure 16.
Voltage
+12V

Figure 16 Digital input voltage range

When used as a digital input, the universal input can measure frequencies up to 10 Hz (600
pulses per minute). The minimum pulse width detectable is 50 milliseconds.
Dry contact, push buttons, magnetic reed switches or PNP transistors must supply voltage to
the digital input for correct operation.
To use the universal input as a digital input
1. Connect the appropriate digital signal to the universal input according to the diagrams
below.
2. Configure the digital input type and then calibrate using the OpenBAS software.
Table 6 shows how to connect a device to the digital input.

Table 6 Digital Input Wiring

Type of field device Notes
Dry contact or high
switched PNP transistor
28 (40)
Input
10V
8V
6V
4V
2V
0V
Valid
Uncertain
ZERO
region
region
24 VDC power supply to feed
the dry contact switches
Valid
ONE
region
Wiring diagram
Field Device
Field wiring
Controller
24VDC
24V
UI#
0V
0V