CHAPTER 1: COMMUNICATIONS GUIDE
ETHERNET INTERFACE
345 TRANSFORMER PROTECTION SYSTEM – COMMUNICATIONS GUIDE
1–33
This is a function used to quickly read the status of a selected device. A short message
length allows for rapid reading of status. The status byte returned will have individual bits
set to 1 or 0 depending on the status of the slave device. For this example, consider the
following 350 general status byte:
The master/slave packets have the following format:
Query
:
Response
:
08H Diagnostics
Just respond, no action required for now.
Serves as a loopback test.
Outgoing message for this function is the same as input one.
16 (10 Hex) Preset Multiple Registers
Presets values into a sequence of holding registers (4X references.
Query
:
The query message specifies the register references to be preset. Registers are addressed
starting at zero: register 1 is addressed as 0.
The requested preset values are specified in the query data field. Data is packed as two
bytes per register.
Here is an example of a request to preset two registers starting at 43851 to 00 01 and 00
00 hex, in slave device 254:
Mask
Function
0x01
Alarm
0x02
Trip
0x04
Self Test Fault
0x08
Breaker Connected
0x10
52a Status
0x20
52b Status
0x40
Maintenance
0x80
In Service
Field Name
Hex
Slave Address
FE
Function
07
Field Name
Hex
Slave Address
FE
Function
07
Device Status (see definition above)
2C