Communication protocols
PROGRAMMING MANUAL
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1
.0
To access the VR memory area, execute the command
ETHERNET(1,-
1,9,0)
. This is the default setting at power-up. To access the TABLE memory
area, execute the command
ETHERNET(1,-1,9,1)
.
Trajexia can exchange data in the holding registers via the ModbusTCP
protocol. Trajexia supports 16-bit signed integer values and 32-bit IEEE
floating point values. The data format used is defined by a parameter of the
ETHERNET
command. To exchange holding registers values as 16-bit
signed integers, execute the command
ETHERNET(1,-1,7,0)
. This is the
default setting at power-up. To exchange holding registers values as 32-bit
IEEE floating point, execute the command
ETHERNET(1,-1,7,1)
.
More information on the Modbus protocol and the communication messages
format can be found in the MODBUS APPLICATION PROTOCOL
SPECIFICATION document, which can be downloaded at
http://www.Modbus-IDA.org.
4.2.5
EtherNet/IP protocol
EtherNet/IP is an industrial multi-vendor network that uses Ethernet
components. The EtherNet/IP specifications are open standards managed
by the ODVA (Open DeviceNet Vendor Association), just like DeviceNet.
EtherNet/IP is not just a network between controllers; it is also used as a
field network. Since EtherNet/IP uses standard Ethernet technology, various
general-purpose Ethernet devices can be used in the network.
The EtherNet/IP protocol supports implicit communications, which allows
cyclic communications with EtherNet/IP devices. Data can be exchanged at
high speed between Controllers and devices. TJ2-MC64 can exchange a
maximum of 512 bytes per end-point.
The meaning of the data is defined when the connection between the client
and server end-points is established.
The client opens a connection with an endpoint on the server (the
Controller). The type of data exchanged is determined by defining the
endpoint on the Controller. The CIP Assembly object, instances 100 (input to
the Controller) and 101 (output from the Controller) are used and mapped to
the required
VR
or TABLE memory on the Controller. This mapping is
defined at run-time using the
ETHERNET
command.
The memory area on the controller with which the endpoint is associated,
and the format of the data exchanged is determined by configuring
parameters on the endpoint using the ETHERNET command.
The ETHERNET command function index '14' is used to access the
endpoints, as follows:
ETHERNET(action, unit_number, function, endpoint_id,
parameter_index [,parameter_value])
•
action
0 = Read, 1 = Write.
•
unit_number
-1
•
function
14
•
endpoint_id
/i
•
parameter_index
, parameter_value
/i
Examples
Set endpoint 1 to VR data type, and data format to 32 bit floating point:
Index
Value
Description
1
Assembly Object, Instance 100
Input to the controller
2
Assembly Object, Instance 101
Output from the controller
parameter_index
parameter_value
Value
Description
Value
Description
0
Address
--
Start address (default = 0)
1
Data type
3
VR (default)
4
TABLE
2
Data format
0
16 bit integer (default) (2 byte element)
1
32 bit integer (4 byte element)
2
32 bit floating point (4 byte element)
