Control Signals Overview; Installing Bypass Control Wiring; Figure 4-22: Simplified Can And Pull-Chain Wiring For Parallel Ups System - Eaton 93PR Installation And Operation Manual

4.11.2.

Control Signals Overview

Two controls signals (External CAN Network, Bypass Pull-Chain) are required for external
paralleling. Both of these control signals are fault tolerant and alarmed when disconnected.
External CAN (ECAN)
ECAN provides means for communications between the UPS's in a parallel system. The system
will continue to share load and protect the load when this network fails.
Bypass Pull-Chain
Bypass Pull-Chain is an open collector signal that goes low when the Bypass static switch of
any UPS is online. When External CAN (ECAN) is down, the pull-chain is low, and the UPS is
online, the UPS will lock to and transfer to bypass. Service can manually short this signal in
some rare failure modes to force a system transfer to bypass.
Signal Inputs Actions
Each UPS has maximum eight signal inputs, 5 native and one in each Mini-slot when using a
suitable connectivity device. These inputs can be configured with action items. The following
action items affect all UPSs in the system.
Wiring EPO switch in parallel
It is recommended to use separate EPO circuit for each parallel unit.
4.11.3.

Installing Bypass Control Wiring

1. During the installation, follow all the safety instructions given in the 93PR User's and
Installation Guide.
2. 12-pin terminal block for external parallel control signals is accessible on the right side of
the communication interface, on the top section of the UPS.
3. The Phoenix Contact

Figure 4-22: Simplified CAN and Pull-Chain Wiring for Parallel UPS System

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