49
CAUTION!
When channel reservation and Routing are used simultaneously,
channel reservation has higher priority. Routing table is used only
without channel reservation! In case of channel reservation, all
frames are sent to one recipient regardless of format and length of
the frame. After channel is released (after channel reservation time
has elapsed), the recipient is found on the basis of the address field
of received frame.
8.2.5.2. Modbus RTU Master mode
MT-101 Module operating in
Modbus RTU Master
mode receives data sent by peripheral
device operating in Modbus RTU Master mode at PORT2. Data are sent via GPRS to
remote Slave devices according to routing table.
Module MT-101 operating in this mode acts as intelligent GPRS communication gateway
allowing physical separation of Modbus RTU network nodes. Module's internal resources
have assigned Modbus ID which allows reading them from PORT2.
8.2.5.2.1. Routing table size
Function
- Defines size of routing table
Data type
- number
Range
- 1....255
Default
value
- 1
Comments
- the length of routing table should not be shorter than number
of network nodes the module communicates with.
8.2.5.2.2. Routing table
Idx
- index number of the list
number IP
- IP address of GPRS network node
number ID
- Modbus ID number (0-255) of slave device connected to GPRS
network node with given IP address
Comments
- entering Modbus ID of one of the Slave devices connected to
PORT2 (including internal module resources) results in sending
replies from that ID to specified IP address regardless of the
address of inquiring unit. Setting this value to
0
(
zero
)
, makes
the module with specified IP address receive all frames sent by
Master unit regardless of Modbus addressing.
8.2.5.3. Modbus RTU Slave mode
MT-101 Module operating in
Modbus RTU Slave
mode sends all received via GPRS
queries to PORT2, except those that have Modbus IDs identical with module's own
Modbus ID of internal resources in address field - since they are handled locally.
replies received at PORT 2 from peripheral Slave devices along with replies from internal
module resources are sent to the address from which query was issued or according to
Routing Table content.
Содержание MT-101
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