4-6 735/737 Feeder Protection Relay
GE Power Management
4.2 SUPPORTED MODBUS FUNCTIONS 4 MODBUS COMMUNICATIONS
4
4.2.4 FUNCTION CODE 05: EXECUTE OPERATION
Modbus Implementation: Force Single Coil
735/737 Implementation: Execute Operation
This function code allows the master to request the 735/737 to perform specific operations. The operations that can be
performed by the 735/737 are as follows:
Simulation and I/O test commands are for production testing and training simulation. Commands 02 - 07 will be ignored
unless communications "TEST" switch 8 is on. When a REMOTE SETTINGS command is received (TEST switch=on) the
front panel switch settings are replaced by the dial settings loaded into setpoint memory. Send command NORMAL SET-
TINGS to restore selection of front panel dial settings. If command SIMULATION ON is sent the actual phase and ground
current are replaced by the pre-loaded values in setpoint memory. The relay will respond as if these are the actual dial set-
tings and measured current values. This mode continues until power is lost or until the command "SIMULATION OFF" is
received or TEST switch 8 is set to off. Setpoints used in this mode are stored in RAM memory and are erased when con-
trol power is lost. The relay may behave erratically if invalid values are loaded into setpoint memory.
To turn on relays, LEDs and the bargraph under computer control for testing purposes, the appropriate I/O test patterns are
first loaded as setpoints using STORE SETPOINTS function 06 or 16. Then command "TEST I/O ON" is issued. Normal
relay control of this I/O hardware is suspended and the test patterns in setpoint memory are substituted. This continues
until a "TEST I/O OFF" command is received or control power is removed or TEST switch 8=off.
During testing, normal protection is disabled. As a safeguard, all test and simulation commands are ignored unless switch 8
is in the TEST on=1 position.
Message Format and Example:
Request slave 11 to execute operation code 1 (clear trip indicators).
OPCODE FUNCTION DESCRIPTION OPCODE FUNCTION DESCRIPTION
01 clear clear trip indicators 08 disable watchdog reset main processor
02 remote settings simulation dials 09 enable service activate service relay & indicator
03 normal settings front panel dials 0A disable service deactivate service relay &
indicator
04 simulation on simulation currents
05 simulation off actual currents 0B disable relays disable output relays
06 test I/O on setpoint control of I/O 0C enable relays enable output relays
07 test I/O off normal control of I/O 0D clear last trips clear 5 causes of last trips
MASTER TRANSMISSION: BYTES EXAMPLE / DESCRIPTION
SLAVE ADDRESS 1 11 message for slave 11
FUNCTION CODE 1 05 execute operation
OPERATION CODE 2 00 01 operation code 1 = clear trip indicators
CODE VALUE 2 FF 00 perform function
CRC 2 ?? ?? CRC calculated by the master
SLAVE RESPONSE: BYTES EXAMPLE / DESCRIPTION
SLAVE ADDRESS 1 11 response message from slave 11
FUNCTION CODE 1 05 execute operation
OPERATION CODE 2 00 01 operation code 1 = clear trip indicators
CODE VALUE 2 FF 00 perform function
CRC 2 ?? ?? CRC calculated by the slave
To Next Page
Loading...
