Message Frame Separation; Provided Data; Contents Of List Of Signals; Live Bit - Man L23/30DF Project Manual

MAN Diesel & Turbo

2.3 Message Frame Separation

2.4 Provided Data

2.4.1 Contents of List of Signals

2.4.2 Live Bit

Function Function Code
Code (hexadecimal)
22 0x16
23 0x17
Message frames shall be separated by a silent interval of at least 4 character
times.
Provided data includes measured values and alarm or state information of
the engine.
Measured values are digitized analogue values of sensors, which are stored
in a fixed register of the Control Module Small. Measured values include me-
dia values (pressures, temperatures) where, according to the rules of classifi-
cation, monitoring has to be done by the machinery alarm system. The data
type used is signed integer of size 16 bit. Measured values are scaled by a
constant factor in order to provide decimals of the measured.
Pre-alarms, shutdowns and state information from the SaCoS
available as single bits in fixed registers. The data type used is unsigned of
size 16 bit. The corresponding bits of alarm or state information are set to the
binary value „1", if the event is active.
For detailed information about the transferred data, please refer to the "list of
signals" of the engine's documentation set. This list contains the following in-
formation:
Field Description
Address The address (e.g.: MW15488) is the software address used in the
Control Module Small.
HEX The hexadecimal value (e.g.: 3C80) of the software address that has
to be used by the Modbus master when collecting the specific data.
Bit Information of alarms, reduce load, shutdown, etc. are available as
single bits. Bits in each register are counted 0 to 15.
The dedicated denomination of the measuring point or limit value as
Meas. Point
listed in the „list of measuring and control devices".
Description A short description of the measuring point or limit value.
Unit Information about how the value of the data has to be evaluated by
the Modbus master (e.g. „°C/100" means: reading a data value of
„4156" corresponds to 41,56 °C).
Origin Name of the system where the specific sensor is connected to, or
the alarm is generated.
Signal range The range of measured value.
In order to enable the alarm system to check whether the communication
with SaCoS is working, a live bit is provided in the list of signals. This Bit is al-
ternated every 4 seconds by SaCoS. Thus, if it remains unchanged for more
than 4 seconds, the communication is down.
Description
mask write register
read write multiple registers
system are
one
3