User guide

eWON 500-2001-4001-4002 User Guide - eWON Configuration
eWON 500®2001®4001®4002® Version 4_3_0 - User Guide - 10/5/05 - ©ACT'L sa - Page 63
• Historical and real-time logging:
Those fields display only for some eWON's versions (c.f. “Tags monitoring and handling” on page 57)
4.4.2.1.1 Publish as Modbus TCP
This feature allows accessing Tag Value through Modbus/TCP. In that configuration, eWON acts as a slave. Actually, there is no data map as in
most PLC, instead of that you define Tag by Tag its Modbus TCP address.
4.4.2.1.1.1 Defining the Modbus TCP address
There are 4 types of Modbus variable, Contact (RO), Coil (RW), Input Register (RO), Holding register (RW). The type selected for the Tag you
want to publish will depend on its type:
Usually, the RO or RW property of a Tag is obvious. But in case of doubt, you can confirm the type by checking the View IO for the Tag:
• Remove the "Force Read Only" option in the Tag configuration (disabled by default).
• Check the View IO page, if the Tag has an update field, it means it is a RW Tag otherwise the Tag is RO.
• The address selected will be the address of the Modbus 16 bit register. The address range starts with register 1 (in the Modbus frame,
eWON register 1 is transmitted as 0).
• Publish as float
The eWON supports accessing Tag values as float registers. The float is published with the IEEE representation and the value can be read on 2
consecutive registers, with the first register starting at the user defined address.
Historical and real-time logging
Historical logging
enabled
If checked, the Tag values will be logged.
Warning: this is a non-volatile logging; data are stored in the flash file system. All the data are stored in
the same file, the maximum number of values that can be saved is from 16384 to 139264, depending on
the way you have setup the resources storage in the eWON (when maximum size is reached, then the
older data will be erased first).
If one Tag is changing very often and another Tag is changing rarely, the first value will obviously
overwrite the second Tag’s values because of the circular storage mechanism.
Logging dead band Defines the dead band of the Tag’s incremental recording (use negative value to disable it)
Logging Interval
Defines the interval, in seconds, for the Tag recording (set to zero to disable logging interval).
Can be used at the same time as logging dead band.
Real time enabled
If checked, the Tag values will be logged in memory.
Real time logging is different from historical logging because data are saved in a circular memory buffer.
The other difference with historical time logging is that incremental recording is not possible, only fixed
interval recording can be performed.
Time span Defines total logging window time in seconds.
Logging Interval Defines the interval, in seconds, of the Tag recording
Table 41: Historical and real-time logging controls
Tag property Modbus data type
Boolean, RO Contact
Boolean, RW Coil
Analog, RO Input register
Analog, RW Holding register
Table 42: the 4 Modbus variable types