Leveraging Power of Wireless
®
Manual SG151lite
9
2.3.4.1
Modbus Interfacing
When SG151lite is configured as described in the previous chapter, you can start the
Modbus Master
to read status and sensor data over ModbusTCP. As a
Modbus Slave Device, SenzaGate
will respond
to the Modbus Master’s read requests. The Master must send Modbus-Function
4 (0x04) – Read
Input Registers
with
Slave-ID=1, Port=502
and the correct
IP-Address of the Gateway.
The return
values of the Modbus Slave are given as
16bit registers
as defined by the Modbus configuration. For
each SenzaBlock MAC-ID, 25 registers are reserved using the following layout:
Register 1-4: MAC-ID
Register 5:
SenzaBlock Type
Register 6-11: Sensor Values
Register 12-13: Alarm Indicator
Register 14-19: Timestamp
Register 20:
Battery Status
0 = Empty / 1= Full / 2 = ext. Power
Register 21:
Linkquality of Wireless Link
255 = Max. / 0 = Min.
Register 22:
Device Status
1= Connected / 0 = Disconnected
Register 23-25: Not used
Example for MAC-ID 001EAA000000020D, SB110-NTC:
-------- MAC-ID --------
Register 1: 001E
Register 2: AA00
Register 3: 0000
Register 4: 020D
--- SenzaBlock Type ---
Register 5: 0077
Hex
= 119
Dec
(SenzaBlock Type: SB110-NTC)
---- Sensor Values ---
Register 6: Sensor Value – 1
st
interface
Register 7: Sensor Value – 2
nd
interface / Overflow 1
st
interface in case of SB110-PI)
Register 8: Sensor Value – 3
rd
interface / 2
nd
interface in case of SB110-PI)
Register 9: Sensor Value – 4
th
interface / Overflow 2
nd
interface in case of SB110-PI)
Register 10: not used
Register 11: not used
----- Alarm Flags -----
Register 12: Indicate alarm-type of CH1 and CH2, reset with next “regular” data point
Register 13: Indicate alarm-type of CH3 and CH4, reset with next “regular” data point
----- Timestamp -----
Register 14: Year
Register 15: Month
Register 16: Day
Register 17: Hour
Register 18: Minute
Register 19: Second
----- Status -----
Register 20: Battery Status 1= Full / 0 = Empty
Register 21: Linkquality
255 = Max. / 0 = Min.
Register 22: Device Status
1= Connected / 0 = Disconnected
No message for last 5 heartbeats
“Disconnected”
