Emerson AC4 user manual Controller board components continued, Introduction

				Introduction
Table 1	Controller board components (continued)
Item		Description		For more information, see:
		One of four output jumpers. Each digital output has a
		jumper to set the fail-safeposition of the output point when	3.2.3: Setting the Digital Output
I - Digital output		power fails. The OFF position makes the contact Normally
				Jumpers
loss-of-power		Open (factory default). The ON position makes the contact
			7.6.4: Configure Output for Loss of
jumper		Normally Closed.
				Power (“Fail-Safe”)
		Note: The jumper position has no effect on the contact
		when the Liebert AC4 has power.
		Each of the four input connections is a two-state point:	3.0:	Wiring and Connections
J - Digital input		ON/OFF (energized/de-energized).	3.2.1: Connecting Digital Inputs
connectors		An example of a field digital input is a Liebert	5.4:	View Input Status
		Environmental unit’s common alarm relay output.	7.3:	Setup System - Setup Inputs
K - Digital input		Each input has an LED to indicate its status: ON/OFF	1.7:	LED Indicators
status LEDs		(energized/de-energized).
L - Serial interface		Connection for laptop or video terminal. Used for	3.4:	RS232 Connector
		configuration and monitoring using the Service Terminal
connector			A.2:	Connecting to the Service
		Interface. Requires a null modem cable for connectivity
(RS232/EIA574)				Terminal Interface
		(P/N 201258P1).
M - DIP switch 1		DIP switch used for resetting password to default.	7.7.1: Change Password
N - LCD connector		Connection for the LCD on the enclosure door.	N/A
O - LCD contrast		Adjustment contrast for the LCD on the enclosure door.	N/A
adjustment
P - 24VAC power		Power connection for the controller. Requires 24VAC.	2.4:	Connect Power to the Liebert
connector				AC4

5 Liebert® AC4™