Modbus Registers OPTIMA...BLC1MOD

VAV-Compact
Volumetric flow compact control device
2 VAV-Compact Modbus Register • en-gb • 2019-03 • Subject to changes www.belimo.com
Modbus General Notes
General information
Date 25.03.2019
Product Name VAV-Compact
Actuator type ..MV-D3-MOD, LHV24A-D3-MOD
Protocol Modbus RTU over RS-485
Modbus RTU
Transmission formats 1-8-N-2, 1-8-N-1, 1-8-E-1, 1-8-O-1 (Default: 1-8-N-2)
Baud rates 9‘600, 19‘200, 38‘400, 76‘800, 115’200 Bd
(Default: 38‘400 Bd)
Address 1...247 (Default: 1)
Number of nodes Max. 32 (without repeater)
Terminating resistor 120
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Parameterisation
Tool ZTH EU
Quick adressing
Actuators support quick addressing via the „Address“ and „Adaption“ buttons.
For detailed, information please see product datasheet (chapter Service).
Register implementation
All data is arranged in a table and addressed by 1..n (Register No.) or 0..n-1 (Address). No distinction
is made between data types (Discrete Inputs, Coils, Input Registers and Holding Registers). As a
consequence, all data can be accessed with the two commands for Holding Register. The commands
for Discrete Inputs and Input Registers can be used as an alternative.
Commands
Standard commands:
Read Holding Registers [3]
Write Single Register [6]
Optional commands:
Read Discrete Inputs [2]
Read Input Registers [4]
Write Multiple Registers [16]
Command „Read Discrete Inputs“
The command reads one or more bits and can alternatively be used for Register No. 105
(Malfunction and Service information).
Example
The start address to be used is 1664 → 104 (Register Address) * 16 (Bit) = 1664
Interpret values in the registers
All values in the register are unsigned integer datatypes.
Example
Read (Function 03, 1 Register) Value Register No. 12 = 0001‘1010‘1100‘10002 = 6‘85610
Actual Value = Value * Scaling factor * Unit = 6‘856 * 0.01 * m3/h = 68.56 m
3
/h
32-Bit values in two registers
Values that exceed 65,535 are stored in two consecutive Registers and have to be interpreted as
„little endian“ / LSW (Least Significant Word) first
Example
Register No. 10 (AbsFlow LowWord) = 14,55110 = 0011‘1000‘1101‘0111
2
Register No. 11 (AbsFlow HighWord) = 1910 = 0000‘0000‘0001‘0011
2
AbsFlow HighWord AbsFlow LowWord
19 14,551
0000‘0000‘0001‘0011
2
0011‘1000‘1101‘0111
2
AbsFlow = 0000‘0000‘0001‘0011‘0011‘1000‘1101‘0111
2
= 1,259,73510 = 1259.735 l/h
Math formula:
AbsFlow = ( AbsFlow HighWord * 65,536 ) + AbsFlow LowWord
AbsFlow = ( 19 * 65,536 ) + 14,551 = 1,259,735 = 1259.735 l/h
Deactivated registers
If a register is not supported by a device or by a device setting it is indicated
with 65‘535 (1111‘1111‘1111‘1111
2
).
!
All writeable registers on registers >100 are persistent and are not supposed to be written on a
regular base.