MODBUS REGISTERS
EATON PowerXpert®Gateway Series 1000 Card User’s Guide S164201670 Rev 1 67
Breaker Alarms (FC 01 or 02)
There are two alarms for each circuit breaker: Overload Warning and
Overload. Each alarm has a unique address similar to the data registers,
but these alarms are not data registers. The alarms are discrete inputs
and are read using FC 01 or FC 02 in the Modbus program.
Table8. Breaker Alarms (FC 01 or 02)
Name Coil/StatusAddress DataType
BranchBreaker 1 Overload Warning 1000 BOOL
BranchBreaker 1 Overload 1001 BOOL
Table 8 shows the alarms for Breaker #1. Determine the corresponding
alarms for other breakers by using the following formula:
Breaker #5 address = ((Breaker number – 1) x 2) + Breaker #1 address
For example, to find the Overload Warning alarm address for Breaker #5:
Breaker #5 Overload Warning = ((5 – 1) x 2) + 1000
= ((4) x 2) + 1000
= (8) + 1000
= 1008
To find the Overload alarm address for Breaker #20:
Breaker #20 Overload = ((20 – 1) x 2) + 1001
= ((19) x 2) + 1001
= (38) + 1001
= 1039
To read the Overload Warning alarm for Breaker #5 in Panel #8, the
Modbus program would be set as follows:
IP: <IP address of PDU/RPP>
Unit ID: 25
Starting Register: 1008
Number of registers: 1
Function code: 02
The Modbus program would return a true/false value of the Overload
Warning alarm for Breaker #5 in Panel #8 of the PDU/RPP at the
specified IP address.