User Manual

2
Modbus Interface Specifications
Modbus Data Model
20
Building Technologies
A6V10316242_a_en
CPS Fire Safety
31.05.2019
Date and Time
DateTime (Holding registers, default base address: 1060)
Three holding (read/write) word registers used for reading or synchronizing the
NK823x date and time.
The synchronization must be enabled in the configuration settings and results, in
turn, in the synchronization of the fire system (FS20 and then STT20 via FS20).
Alternatively, if the synchronization on these registers is not enabled, the NK823x
gateway gets date and time periodically from the fire system (FS20). In this case,
writing to the registers is disabled, and a Modbus error code 0x04 is returned when
trying a write command.
When synchronization occurs, all registers should be written in sequence to
prevent any possible data interpretation error. The NK823x gateway acquires the
new time stamp when the last of the 3 values is written.
The three 16-bit registers are organized in 6 byte containing 6 hexadecimal values
corresponding with day, month, year, hour, minute, and second respectively.
Word / Bit
Information
Notes
0 / 0-7
Day
1-31 code in hexadecimal, e.g. 1B hex for day 27.
0 / 8-15
Month
1-12 code in hexadecimal
1 / 0-7
Year
10-99 code in hexadecimal
1 / 8-15
Hour
0-23 code in hexadecimal
2 / 0-7
Minute
0-59 code in hexadecimal
2 / 8-15
Second
0-59 code in hexadecimal
Note: For detailed information about the time synchronization options on the
Modbus host interface, refer to the Modbus interface configuration section of the
NK8237 Installation, Configuration, and Commissioning manual (document no.
A6V10316241).
2.2.2.3 Status Tables
The status tables include an input word register per object. The number of tables
depends on the specific systems whose object list is defined at configuration time.
For example, there may be 8 area registers corresponding with 8 areas of a given
fire system.
The list of object types includes:
Area
WT_Area (Input registers, default base address: 6500)
Bit
Information
Notes
0 (lsb)
Non-default mode
Default range for possible abnormal mode
1-3
—
Not used
4
WalkTest
1)
Walktest active
5
Manned
Set in day (attended) mode
6
Test
1)
Set in test mode
7
Off
1)
Excluded
8
Non-default value
1)
Abnormal condition such as alarm output(s) disabled or other
states resulting in a reduced safety
9-15
—
Not used
1)
Available only for versions up to MP4.0.