8
WARNING
Risk of
Electric Shock
and
Fire
. The battery circuit is grounded at the UPS. Do not attempt to
additionally ground the battery circuit. Otherwise, maintenance personnel may be exposed to an
electrical shock hazard that could result in death or injury, or damage to the UPS or its electrical
loads may occur.
Before any work is begun on a Mesta External Battery Cabinet, refer to Chapter 9, “External Battery
Cabinets”, of this manual for complete instructions and detailed wiring diagrams.
2.2 COMMUNICATIONS LINKS (Rear Panel Hardware Configuration)
The communication hardware connectors on the back panel of the UPS consist of a 25-pin for RS232
compatible or current loop serial communications, a 15-pin for custom I/O, and either a 25-pin for 6
signal level relays or a 12-pin for 4 power relay contacts.
•
The serial communications connector provides a means for monitoring and/or controlling the
UPS remotely from a computer or terminal via RS232 signaling or 25 ma current loop methods.
Two LEDs on the panel just above the RS232 connector are used to diagnostically indicate
current flow through the TRANSMIT/RECEIVE portions of the 25 ma current loop
communications link if the serial communications is configured in this manner. (Note: current
loop is a method of interconnecting terminals and transmitting signals whereby a mark (binary 1)
is represented by current on the line, and a space (binary 0) is represented by the absence of
current.)
•
The custom I/O connector allows for 4 standard dry contact inputs. If a dry contact is used to
short pins 1 and 2 of this connector, the UPS will shut down and trip its own breakers. This is
referred to as a remote shutdown and is used by fire protection or other safety equipment to turn
off the UPS in the event of an emergency. (The remote shutdown is an optional feature. Please
contact the factory for activation of this function.) A dry contact across pins 3 and 4 results in an
audible alarm reset in the remote status panel should "mode 1" be employed to control the
status relays. Pins 14 and 15 provide -12V and +12V supply power to a remote status panel or
custom setup. Other pins can be customized for specific requirements of the end user of this
equipment.
•
The relay contacts connectors have dry contact outputs that can be used by the UPS to control
external equipment. The most frequent use is with a remote status panel, where these contacts
are used to control the lights and audible alarm on the panel. Your UPS will come with one of
two types of relay contacts. If your UPS has a 25 pin connector for relay contacts, your unit is
equipped with six low level 24V, 0.1 amp maximum, contacts. If your UPS has a 12 pin
connector for relay contacts, your unit is equipped with four power 120VAC, 10 amp maximum
contacts.
