DB-9 Connector, Communications, DB-9 pin assignment

8.0COMMUNICATIONS

8.1DB-9 Connector

Table 1 DB-9 pin assignment

8.2Remote Shutdown Via the DB-9 Connector

PSITM specifications

DB-9 Pin Assignment Description

8.2.1Any Mode Shutdown—Via Pins 5 & 6

8.2.2Battery Mode Shutdown—Via Pins 4 & 5

Communications

The UPS has a DB-9 (9 pin female) connector on the rear to allow UPS status communications with a computer system running MultiLink software. The DB-9 is capable of supplying serial communica- tion, on battery and low battery signals. MultiLink, Liebert’s UPS monitoring and shutdown soft- ware, is shipped with the UPS, along with a 3m (10 ft) DB-9 cable required for running MultiLink.

When MultiLink is installed on the host computer, the UPS can signal “on battery” and “low battery” using opto-couplers. When the UPS is operating in Battery mode, it can receive a signal from the host computer system that will shut down the UPS (after gracefully shutting down the operating system on the host computer system) when the remaining battery run time is low. The timing of the signal depends on MultiLink’s configuration settings. This shutdown signal (5-12VDC) must have a dura- tion of at least 2 seconds for the UPS to be shut down. The UPS communicates via serial communica- tions using Liebert ESP II protocol.

1Low Battery (open collector)

2 UPS TxD

3 UPS RxD

4 Battery Mode Shutdown (5-12V)

5Common

6Any Mode Shutdown (short to pin 5)

7 Low Battery (open emitter)

8 Mains Fail (open emitter)

9 Mains Fail (open collector)

The PowerSure PSI can be shut down remotely by shorting Pins 5 and 6 or via Pins 4 and 5 of the DB-9 connector.

When Pin 6 is shorted to Pin 5, the UPS output is shut Off regardless of what mode the UPS is oper- ating in. The UPS cannot be started as long as the pins are shorted. When the short is removed, the UPS output can be enabled by pressing the ON/Alarm Silence/Battery Test button.

While the UPS is operating on battery (with no battery test in progress), a 5-12VDC signal for 2 sec- onds or longer is required to signal a shutdown. Signals for less than 2 seconds are ignored.

After Pin 4 receives the shutdown signal, a 2-minute shutdown timer inside the UPS begins a count- down. The timer cannot be stopped. If mains power returns during the 2-minute timer countdown, the shutdown timer continues until the end of 2 minutes and then the UPS turns Off. By default, autore- start is enabled so the UPS will restart after 10 seconds. If autorestart is disabled via MultiLink soft- ware, the UPS remains Off until a manual restart.

Pin Assignment

Collector to Emitter*

The Liebert PSITM is an advanced power protection system designed to ensure the reliability and efficiency of critical systems in data centers, industrial applications, and mission-critical environments. As the demand for uninterrupted power supply continues to grow, the Liebert PSI serves as an indispensable asset.

One of the main features of the Liebert PSI is its online double-conversion technology. This method guarantees a continuous supply of clean and stable power to connected loads by converting incoming AC power to DC, then back to AC. This process eliminates power disturbances such as voltage sags, surges, and harmonics, ensuring that sensitive equipment operates without interruption.

In addition to its robust power protection capabilities, the Liebert PSI offers scalable solutions to meet varying power requirements. Ranging from 5 kVA to 40 kVA, it can be configured for single or three-phase operation. This flexibility allows businesses to tailor the system to match their specific needs, whether they are expanding data center operations or simply upgrading existing infrastructure.

Another notable characteristic of the Liebert PSI is its energy efficiency. The unit is designed to operate with a high efficiency of up to 94%, which not only reduces operational costs but also minimizes the environmental impact. Moreover, it features an eco-mode that optimizes energy use during non-critical operations without sacrificing reliability.

The Liebert PSI is equipped with advanced communication and management capabilities. It includes an intuitive LCD display for real-time monitoring, enabling users to access vital information about the unit's performance and status. Additionally, it supports various communication protocols such as SNMP and Modbus, allowing for seamless integration into existing management systems.

Furthermore, the Liebert PSI is designed with an emphasis on modularity, allowing for easy upgrades and maintenance. This modular approach reduces downtime and enhances serviceability, ensuring that the system remains reliable throughout its lifecycle.

In summary, the Liebert PSITM stands out as a comprehensive power protection solution that combines cutting-edge technology, energy efficiency, and user-friendly features. Its commitment to safeguarding critical systems against power disturbances makes it a vital component in the infrastructure of any modern data center or industrial setting.