Appendix A - Modbus Communication Port Setting; Viewing/Setting Modbus Setpoints; Network Communication Protocol; Modbus Register Map - Eaton PT 10 Instruction Manual

Appendix A - Modbus Communication Port Setting

Appendix A - Modbus Communica-
tion Port Setting
Modbus communication ports are integrated for certain trip
unit styles. This provides communication from the trip unit to
a field Modbus bus network.
When powered, the trip unit will be able to communicate via
the secondary terminals, labeled MODBA(16), MODBB(17),
and MODBG(18) as a slave device. Recommended Modbus
cable has shielded twisted-pair wires.
A.1 Viewing/Setting Modbus Setpoints
Modbus configuration can be viewed and set from the
LCD display, using the PTM software and through Modbus
communication. To view from Modbus, the settings are
stored beginning at register 404000 and extending through
404003 and may be read by using function code 03 or 04,
listed in Table A1. These four registers can be written one by
one with function code 06 to change the Modbus setting. If
the data written into these registers are out of range, the trip
unit would result in an exception code 03.
Trip units are shipped with a factory set default address of
001, 9600 bits/second baud rate, even parity, and 1 stop bit.
Table A1. Modbus Settings
Modbus
Defintion Register No.
Slave ID 404000
Baud rate 404001
Parity check 404002
Stop bit 404003
A.2 Network Communication Protocol
The trip unit operates only via the Modbus RTU
communication mode.
The trip unit can support a maximum of 122 registers (244
data bytes) in a single Modbus transaction.
The trip unit responds to a limited number of Modbus
function codes. These are function codes 02, 03, 04, 06, 08,
and 16. Function codes 03 and 04 are used interchangeably
to obtain register data.
26 PT UNIT USER MANUAL APRIL 2023 www.eaton.com.cn
Register
Address (HEX) Date Range
0x0F9F 001 - 247
0x0FA0 00 = 9600 bits/s
01 = 19200 bits/s
02 = 38400 bits/s
03 = 57600 bits/s
0x0FA1 00 = None
01 = Odd
02 = Even
0x0FA2 00 = 1 bit
01 = 2 bits
A.3 Modbus Register Map
A.3.1 Input Status (Discrete Inputs)
Input status bits 101001 through 101032 can be read using
function code 02. The status definitions are defined in Table
A2. The first 16 bits are the actual status state while the last
16 bits indicate whether the corresponding status state is
valid or supported by the trip unit.
Table A2. Input Status Definitions
Input Definition
1001 Breaker is in the closed position
1002 Un-acknowledged trip condition
1003 Active or un-acknowledged alarm
1004 0
1005 0
1006 Test mode is active
1007 0
1008 0
1009 0
1010 Long Delay Pickup is active
1011 Zone Selective Interlock (ZSI) is active
1012 0
1013 "Ground" is source ground
1014 0
1015 0
1016 0
1017 Breaker is in the closed position is valid
1018 Un-acknowledged trip condition is valid
1019 Active or un-acknowledged alarm is valid
1020 0
1021 0
1022 Test mode is active is valid
1023 0
1024 0
1025 0
1026 Long Delay Pickup is active is valid
1027 Zone Selective Interlock (ZSI) is active is valid
1028 0
1029 "Ground" is source ground is valid
1030 0
1031 0
1032 0
A.3.2 Real Time Data
The data changing in real time, such as current, voltage,
power, and so on are shown in Table A3. Real time data can
be obtained either in IEEE floating point or in fixed point
format. For data shown in fixed point format, each result
would be the real time data multiplied by a scale factor.
The scale factors are shown as the last column in Table A3.
Energy objects can only be obtained in fixed point format.