25
9400000-J0 Rev C
7.7.2 Digital Inputs
The digital input channels are used to monitor various alarm and control signals. All input channels are voltage
activated and accept a bipolar (negative or positive) DC signal directly.
Connection Method
Typical Alpha systems use the “reset with Hot and trigger with Ground” connection. The digital input is wired in
such a way that the Hot is wired directly into one of the input terminals. For example, the positive input for +24 V
systems. The other input terminal is wired to the Ground (common) of the system through a dry contact relay usu-
ally located on the equipment requiring monitoring. This method allows the digital input to receive or not receive a
Ground signal on an alarm.
Figure 7 — Digital input connection method
Voltage level definitions for digital inputs
The digital input channels can be programmed for “active high” or “active low.” Active high indicates “alarm on
the presence of a ground signal” and active low indicates “alarm on the removal of a ground signal.” See CXC
Software manual for detailed instruction on programming.
Voltage Range (Vdc)
Voltage Level (Vdc)
Considered As “0” (Off)
Voltage Level (Vdc)
Considered As “1” (On)
0 - 60
(system voltage setting)
0 - 3
18 - 60
7.7.3 Analog Inputs
CAUTION!
Ensure the correct polarity is used for all input cable terminations.
The analog input channels are used to monitor various types of electrical signals. Some of the analog channels
are reserved for specific signals, while others are designated as general-purpose inputs, which accommodate
various types of analog signals.
The Battery -48V should be connected at the battery system voltage terminal for CXC reference when a battery
disconnect device is used. It is critical to CXC operation as it ensures a source of power to the CXC should the
disconnect device open the circuit.
Voltage
Voltage Input #1 (load voltage per CXC software) terminals (V1) on the shelf provide connections to an optional
secondary voltage input. For example, this can be terminated to the load side of an LVD contactor to monitor load
voltage.
