EMR-5000
IM02602012E
Communication Protocols
Modbus
®
Modbus
Modbus
®
Protocol Configuration
The time-controlled Modbus
®
protocol is based on the master-slave working principle. This means that the substation
control and protection system sends an inquiry or instruction to a certain device (slave address) that will then be
answered or carried out accordingly. If the inquiry/instruction cannot be answered/carried out (e.g.: because of an
invalid slave address), a failure message is returned to the master.
The master (substation control and protection system) can query information from the device, such as:
Type of unit version;
Measuring values/statistical measured values;
Switch operating position (in preparation);
State of device;
Time and date;
State of the device’s digital inputs; and
Protection-/state pickups.
The master (control system) can give commands/instructions to the device, such as:
Control of switchgear (where applicable, i.e.: each according to the applied device version);
Change-over of parameter set;
Reset and acknowledgment of pickups/signals;
Adjustment of the date and time; and
Control of pickup relays.
For detailed information on data point lists and error handling, please refer to the Modbus
®
documentation.
To allow configuration of the devices for Modbus
®
connection, some default values of the control system must be
available.
Device Planning Parameters of the Modbus
Parameter
Description
Options
Default
Menu path
Mode
Mode
RTU,
TCP
RTU
[Device Planning]
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