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PT UNIT USER MANUAL
APRIL 2023 www.eaton.com.cn
6. PT Communication Features
6. PT Communication Features
6.1 Integrated Modbus-Remote Terminal
Unit (RTU) Port
A Modbus communication port is integrated into the PT20/25
trip unit. The trip unit responds to messages from the master
using the Remote Terminal Unit (RTU) protocol. Modbus port
configuration can be viewed and set using the display and
navigation buttons or using Power Trip Protection Manager
software (See Section 7.2)
Table 10. Factory Defaults
The trip unit uses Modbus function codes 02, 03, 04, 06, 08,
and 16 and supports up to 122 registers (244 bytes) in a single
Modbus transaction. The detailed Modbus register map is shown
in Appendix A - “Modbus Communication Port Register Map”.
6.2 USB Port
The PT series includes a micro-B USB port on the front of the trip
unit. This USB connection may be used in conjunction with the
Power Trip Protection Manager software to configure, control,
and test the trip unit.
The USB can be used to supply power to the trip unit, change
and save relevant settings.
7. Important System Components
7.1 Auxiliary Power
Providing auxiliary power to the PT unit will provide full
functionality even when the circuit breaker is open or when
the circuit breaker is under very light load such that the self-
powering current sensor cannot provide sufficient energy to
fully power the trip unit. Auxiliary power is connected to the
circuit breaker's secondary terminal block.
7.2 Power Trip Protection Manager (PTM)
Configuration Software
Eaton's PTM is a Windows-based software that configures,
controls, and tests Eaton PT 10/20/25 trip units. The user
can create, modify, and save setting configurations for PT
10/20/25 trip units. The software further allows the user
to reset trip units, adjust trip unit's date and time, capture
current or voltage waveforms, and perform trip or no-trip
tests.
The software is available as a download from the following
link:
http://www.eaton.com.cn/PTM
Factory Default Options
Slave address
001
001 to 247
Baud Rate
9600
9600, 19,200, 38,400, 57,600
Parity
Even
Even, odd, none
Stop bits
1
1 or 2
IMPORTANT
Auxiliary power is required to provide protection feature.
