Trox Technik FSL-CONTROL II, Installation And Configuration Manual, Page: 71 / 80

Configuring interfaces to the central BMS
Modbus RTU interface
Single room control system FSL
‑
CONTROL II 71
7
Modbus register
The SPI interface protocol defines commands for sending and for receiving useful
data. Each of these SPI commands is assigned a Modbus register. The SPI
interface reads certain registers and writes to others, depending on the
command. It is, however, possible to read all Modbus registers and to write to
all Modbus registers.
The sequence of the registers is the same as the sequence of the commands of the
SPI interface. Each Modbus register is 2 bytes.
The contents of the registers is the same as the useful data of the SPI
interface. In the only re-encoding step, the high byte and the low byte of the
SPI interface are distributed to different Modbus registers as required; see the
SPI byte column.
List of registers for X-AIRCONTROL
Direction column: EM = expansion module, GG = base device
Modbus values column:
uint16 = integer without prefix
sint16 = integer with prefix
0 - 100 = value with unit of measure %
0 - 1 = binary values
0 - 2... = Selection of operating modes
SPI bytes column
High, Low Both bytes are identical for Modbus and SPI
Low, (High=0) Only the Low byte is valid, the High byte is deleted
Register
address Useful data
name Direction
EM / GG Modbus
values Modbus
default SPI bytes Encoding / Unit / Resolution
0 ApplicMode EM -> GG 255,
0 – 10,
12 – 14 255 Low, (High=0) 255 = HVAC_NUL
0 = HVAC_AUTO
1 = HVAC_HEAT
2 = HVAC_MRNG_WRMUP
3 = HVAC_COOL
4 = HVAC_NIGHT_PURGE
5 = HVAC_PRE_COOL
6 = HVAC_OFF
7 = HVAC_TEST
8 = HVAC_EMERG_HEAT
9 = HVAC_FAN_ONLY
10 = HVAC_FREE_COOL
12 = HVAC_MAXHEAT
13 = HVAC_ECONOMY
14 = HVAC_DEHUMID
1 Mode EM -> GG 255,
0, 1, 2, 3 255 Low, (High=0) 255 = Nul
0 = Occupied
1 = Unoccupied
2 = Boost
3 = Standby
2 OCCSensor EM -> GG 255,
0, 1, 2, 3 255 Low, (High=0) 255 = Nul
0 = Occupied
1 = Unoccupied
2 = Boost
3 = Standby
3 OutsideTemp EM -> GG sint16 0x7FFF High, Low Unit 0.01°C
4 RoomTemp_Set EM -> GG sint16 0x7FFF High, Low Unit 0.01°C
5 TempOffset EM -> GG sint16 0x7FFF High, Low Unit 0.01°C
6 RoomTemp EM -> GG sint16 0x7FFF High, Low Unit 0.01°C