Modbus TCP
Refer to the user’s guide for a complete parameter list of the equipment.
X
NOTE!
All the parameters are treated as holding registers. Depending on the master that is used, those
registers are referenced starting from the base address 40000 or 4x. In this case, the address
that must be programmed in the master for a parameter is the address showed in the table above
added to the base address. Refer to the master documentation to find out how to access holding
registers.
It should be noted that read-only parameters can only be read from the equipment, while other
parameters can be read and written through the network.
6.4.2
Memory Markers
Besides the parameters, other types of data as bit markers, word or float, can also be accessed using the Modbus
protocol. Those markers are used mainly by the ladder programming function, available for the SRW01-ETH. Refer
to the WLP software documentation for the description of those markers, as well as for the addresses via Modbus.
6.5
COMMUNICATION ERRORS
Communication errors may occur in the transmission of telegrams, as well as in the contents of the transmitted
telegrams. Transmission and connection errors are directly processed by the Ethernet interface and by the TCP/IP
protocol.
In the event of a successful reception, during the treatment of the telegram, the server may detect problems and send
an error message, indicating the kind of problem found:
Table 6.5:
Error codes for Modbus
Error Code
Description
1
Invalid function: the requested function is not implemented for the equip-
ment.
2
Invalid data address: the data address (register or bit) does not exist.
3
Invalid data value:
Value out of the allowed range.
Writing on data that cannot be changed (read only register or bit).
X
NOTE!
It is important that it be possible to identify at the client what type of error occurred, in order to be able
to diagnose problems during the communication.
6.6
STARTUP GUIDE
The following items describe main steps for SRW01-ETH commissioning using the Modbus TCP protocol. These
steps represent an example of use. Refer to specific chapters for details on the steps.
SRW01-ETH | 24
