Operating A Modbus Master - Honeywell EK280 Applications Manual

EK280
Short
Description
Desc.
MBTrM Transfer mode
MBDir Data direction
Device address
MBAdr
(Modbus Slave ID)
MBRSz Register size
MBAMd Addressing mode
Table 5: Preset Modbus parameter
The following connection parameters for connection 1 are set by default via parameter file (see paragraph a)
of this  chapter):
Short
Desc.
Event Connection event
EvTyp Connection event type
Iface Connection interface
SuplT Connection power supply type
TypPr Connection protocol type
Additional information for the
IPInf
connection
i
For communication time window 1 ( chapter 7.1.5.1, paragraph "d)") and the correct APN Data
( chapter 7.1.5.1, paragraph "c)") must be set.

8.2 Operating a Modbus Master

Modbus is a stateless single master protocol. Within the Modbus slave function of the EK280 ( chapter 8.1)
the master (retrieval system) can only retrieve the data from the terminal (slave) during an open time
window. Opened time windows are always linked to increased energy consumption as the time window is
usually open for a longer period of time than what is required for communication and also during this time
e.g. the modem must be ready for reception.
With the Modbus master operation, this energy consumption can be reduced to the required minimum where
e.g. the modem is only switched on for the short period required for transmitting data. In such cases the
retrieval system takes over the role of the slave.
The Modbus master operation serves to send (time and/or) event-driven Modbus data (e.g. register or
archive data) to a slave, or to retrieve e.g. new configuration data or parameters from there.
The EK280 can communicate as a Modbus master by means of the terminal device (external modem) and
the internal modem in any transmission mode (ASCII, RTU, RTU-TCP).
Application Manual
Address Value
2:7B1
2:7B0
2:7B2
2:7B8
2:7B9
Description
Table 6: Default connection parameters
2: TCP - Transmission as for RTU mode with
2
additional information for Modbus TCP protocol
0: H word first  The most significant word is
located in the first register
1 1: L word first  The least significant word is
located in the first register
Info: "H-Byte first" has a fixed setting
1* Value range from 1...247 (0 = "Broadcast")
2 2: Register size 2Byte/16Bit
0: Log. Mode
0
 note in chapter 8.1.7.2, paragraph "d)"
* Value to be determined by the user.
Address Value
1:D70 2F01
1:D75 1
1:D72 3
1:D76 2
1:D77 0
1:D79 0
Content
Content
Call window1 created
1: Period
3: internal modem
2: Battery operation
0: Server (protocol detection)
0: no action
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