Liebert GXT2-4500RT230, GXT2-6000RT230 10.0 C

Communications

10.0 COMMUNICATIONS

The UPStation GXT2 UPS has a standard DB-9 serial port female connector located on the rear of the

UPS unit. Several signals are provided on this port and are assigned as follows:

1. 1. This pin is functional only when the UPS is in battery mode. If the UPS is being powered by the

mains, Pin 4 will ignore any signal on this pin.

2. 2. Pin 4 requires a 5-12 VDC signal to shutdown. This normally comes form the serial port using

Liebert's contact closure cable. It cannot be used with just a contact closure unless the relay is

used to switch a voltage source. A 5-12 VDC signal for 1.5 seconds or greater is required to signal

a shutdown. Signals for less than 1.5 seconds will be ignored. After Pin 4 receives a shutdown

signal for 1.5 seconds, the command cannot be canceled.

3. 3. A battery shutdown signal on Pin 4 will NOT cause an immediate Shutdown. A shutdown

signal will start a 2-minute shutdown timer. The timer cannot be stopped. After 2 minutes, the

UPS will shut down.

4. 4. If the mains returns during the 2-minute timer countdown, the shutdown timer will continue

until the end of 2 minutes and the UPS will turn OFF. The UPS must remain OFF for at least

10 seconds even if AC input power Returns before the UPS turns OFF. This serves to reset and

restart the server.

Whether the UPS turns back ON when power is restored depends on the auto-restart setting: enabled

or disabled.

If the auto-restart is disabled, the UPS will not restart after performing the 2-minute shutdown

delay.

Table 2 DB-9 pin assignment

DB-9

Assignment Description

1 Low Battery (open collector)

2 UPS TxD (typically RS-232 levels)

3 UPS RxD (typically RS-232 levels)

4 Remote Shutdown (5-12VDC, 10-24mA max; battery operation)

5 Common

6 Remote Shutdown (short to pin 5); all modes of operation

7 Low Battery (open emitter)

8 Mains Fail (open emitter)

9 Mains Fail (open collector)

Pin Assignment Collector to Emitter*

* Maximum voltage and current on pins 1, 7, 7 and 9 are 60VDC and 10.0 mA

54321

6789

(-)

(+)

330 Ohms

Open

Collecto

Open

Emitter