Modbus Interface
Page 47
May 2020
DSY-PM-01378-EN-08
Modbus Coil Description Modbus Coil
Notes
Reset Running Totalizer
1
Forcing this coil ON will reset the running totalizer� After
reset, the coil automatically returns to the OFF state�
Reset Grand Totalizer
2
Forcing this coil ON will reset both the running totalizer
and the grand totalizer� After reset, the coil automatically
returns to the OFF state�
—
3…8
Spares
Alarm Set point 1
9
0 = Set point OFF, 1 = Set point ON
Alarm Set point 2
10
0 = Set point OFF, 1 = Set point ON
—
11…16
Spares
Table 7: Modbus coil map
Opcode 01 – Read Coil Status
This opcode returns the state of the alarm coils� The following Coils are defined:
Coil #
Description
9
Alarm Set point 1
10
Alarm Set point 2
11 and up
Spare
Table 8: Read coil status
Command:
<addr><01><00><08><00><02><crc-16>
Reply:
<addr><01><01><0x><crc-16>
Opcode 03 – Read Holding Registers
This opcode returns the input holding registers, such as flow rate or totalizer�
OTE:
N
Each value must be requested individually� Return of a block of registers is not
implemented at this time�
Example requesting flow rate in floating point format�
Command:
<addr><03><00><C9><00><02><crc-16>
Reply:
<addr><03><02><data><data><crc-16>
Opcode 05 – Force Single Coil
This opcode sets the state of a single coil (digital output)� The following Coil Registers
are defined:
Coil #
Description
1
Reset Totalizer
2
Grand Totals
3 and up
Spares
Table 9: Force single coil
The transition of coil from 0 to 1 will initiate function� This bit is auto reset to 0, so there is
no need to set it to 0 after a totalizer reset command�
Command:
<addr><05><00><00><FF><00><crc-16>
Reply:
<addr><05><00><00><FF><00><crc-16>