15
V1.3 | NRG PROFINET User Manual | © 2020 | CARLO GAVAZZI LTD.
EN
5.
Communication
5.1
Cyclic data
The cyclic I/O data exchange is an unacknowledged transmission of real time data between the PROFINET device
and PROFINET controller at a specific rate settable by the user. In the NRG system, cyclic data is exchanged
between the PROFINET Controller and the RG..N solid state relays. The data includes parameters measured by each
NRG solid state relay as well as the control value from the PLC to control each solid state relay. The minimum
permissible rate of exchange for the NRG system is 8ms. Refer to the below tables for the list of information provided
via the cyclic data exchange.
Cyclic Input Data
Index
Data
Data type
0
Hold Current Reading
uint16
1
Voltage RMS Reading
uint16
2
Frequency Reading
uint16
3
Current RMS Reading
uint16
4
Apparent Power Reading
uint16
5
Real Power Reading
uint16
The current measurement is returned as scaled integers. Therefore, a current value of 16.81A will be received as 1681.
The PLC program has to convert the numbers into floating point values. For further information regarding the scaling
of each measurement, refer to the Measurements section in this User Manual.
Note
: ‘Ref’ terminal connection is required for Voltage, Apparent Power and Real Power readings. Otherwise the
readings of these parameters will be 0.
Cyclic Output Data
Index
Data
Data type
0
Control level (0 -100%)
uint8
In case of
ON/OFF
control mode, a control level
< 100%
shall indicate SSR output
OFF
and a control level of
100%
shall
indicate SSR output
ON
.
For the
Power control
firing modes (Burst, Distributed full cycle and Advanced full cycle) the
% control value
shall be
translate to
% power
of the SSR output. Refer to Section 6.2 for more information on Switching Modes.
5.2
Acyclic Data
Acyclic data In PROFINET is used to transfer data that does not require continuous updates or is not critical to the
ongoing process. Any NRG parameter can be set via an acyclic command even if this is included in the start-up
parameters.
To address a particular variable using the PROFINET acyclic command the slot, subslot and index are required.
Slot
Address of NRGC-PN (Always 0) OR
Address of RG..N (1 -32) depending on its position on the NRG bus chain
Subslot
Always
1
Index
The index of the variable (see tables below)
Data Size
The size of the data required
Reading and writing is possible for all variables except for variables related the SSR history as indicated in the tables
below. The datatype of each index is uint16. The indexes are in the form of high byte followed by low byte (big
endian).
