Liebert AC4 用户手册

The digital inputs and outputs are found on the lower right side of the AC4’s printed wiring assembly 

board. This section describes how to connect devices to the AC4’s inputs and outputs.
Each input is tied to an output with the same number:

• Input 1 is tied to Output 1 (default name: Device_1)
• Input 2 is tied to Output 2 (default name: Device_2)
• Input 3 is tied to Output 3 (default name: Device_3)
• Input 4 is tied to Output 4 (default name: Device_4)

Up to four devices may be connected to the AC4. Each device must be connected to an input and an 

output with the same number. 
To determine the proper wire size, see Table 4 - Wiring specifications.

For Liebert environmental units, follow these steps (be sure to connect the same device to inputs and 

outputs with the same number (Input 1 and Output 1, Input 2 and Output 2, and so on): 

• Connect a digital input from the AC4 to the Common Alarm Relay of the environmental unit: 

terminals 75/76 or TB1-6,TB1-7. 

• Connect a digital output (numbered the same as the input) from the AC4 to the Remote Shutdown 

(Power Control) of the environmental unit: terminal 37/38 or TB1-4, TB1-5.

The four digital inputs are found on the lower right side of 

the AC4 just below the output terminal blocks, as shown at 

right. These inputs are numbered 1 through 4.
To connect an input:
1. Turn OFF electrical power to the AC4.
2. If necessary, remove a conduit knockout to permit wire 

entry into the AC4 enclosure.

3. Bring the wire(s) into the AC4 enclosure through a 

conduit knockout or access slot.

4. Loosen the appropriate screw and slip the stripped end 

of the wire into the terminal block.

5. Tighten the screw until it holds the wire snugly.

The four digital outputs are found on the lower right side of 

the AC4 just above the input terminal blocks, as shown at 

right. These outputs are numbered 1 through 4.
To connect an output:
1. Turn OFF electrical power to the AC4.
2. If necessary, remove a conduit knockout to permit wire entry into the AC4 enclosure.
3. Bring the wire(s) into the AC4 enclosure through a conduit knockout or access slot.
4. Loosen the appropriate screw and slip the stripped end of the wire into the terminal block.
5. Tighten the screw until it holds the wire snugly.

To reduce the risk of fire or electric shock, do not interconnect the outputs of different class 2 

circuits.