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6-6
469 Motor Management Relay
GE Power Management
6.2 SUPPORTED MODBUS FUNCTIONS
6 COMMUNICATIONS
6
d) MESSAGE FORMAT AND EXAMPLE, FUNCTION 02
Example 1: Request slave 11 to respond with status of digital inputs 5 to 9:
Digital Input
Status
D1: Access
Closed
D2: Test
Open
D3: Starter Status
Open
D4: Emergency Restart
Open
D5: Remote Reset
Closed
D6: Assignable Input 1
Closed
D7: Assignable Input 2
Closed
D8: Assignable Input 3
Closed
D9: Assignable Input 4
Closed
Bit Mask (LSB)
0111 0001
Bit Mask (MSB)
0000 0001
MASTER TRANSMISSION:
BYTES
EXAMPLE / DESCRIPTION
SLAVE ADDRESS
1
0B
message for slave 11
FUNCTION CODE
1
02
read digital input status
STARTING DIGITAL INPUT
2
00 05
starting at digital input 5
NUMBER OF DIGITAL INPUTS
2
00 05
5 digital inputs (i.e. D5, D6, D7, D8, D9)
CRC
2
A8 A2
CRC calculated by the master
SLAVE RESPONSE:
BYTES
EXAMPLE / DESCRIPTION
SLAVE ADDRESS
1
0B
response message from slave 11
FUNCTION CODE
1
02
read relay coil status
BYTE COUNT
1
02
2 byte bit mask
BIT MASK
2
71 01
bit mask of requested digital input
CRC
2
C5 B9
CRC calculated by the slave