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
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