MTR-3
Installation Instructions
DEIF A/S
Page 18 of 51
Connection
Connection
When connection is selected, load connection and the supported measurements are defined (see
chapter 6, “Measurements” regarding connection mode, on page 23).
Setting of current and voltage ratios
Before setting current and voltage ratios, it is necessary to be familiar with the conditions in which
the device is to be used. All other measurements and calculations depend on these settings. Up
to five decimal places can be set.
Settings range
VT primary
VT secondary
CT primary
CT secondary
Maximum value
1638.3 kV
13383 V
1638.3 kA
13383 A
Minimum value
0.1 V
1 mV
0.1 A
1 mA
Used voltage and current range
Setting of the range is connected with all settings of alarms, analogue outputs and a display
(calculation) of energy and measurements recording, where 100% represents 500 V 5 A. In case
of subsequent change of the range, alarms settings must be correspondingly changed, as well.
Nominal frequency
A valid frequency measurement is within the range of nominal frequency ±32 Hz. This setting is
used for alarms.
Energy flow direction
This setting allows manual change of energy flow direction (IMPORT to EXPORT or vice versa)
in the readings tab. It has no influence on readings sent by communication.
CT connection
If this setting is set to REVERSED, it has the same influence as if CTs would be reversely
connected. All power readings will also change their sign.
Communication
Serial Communication
Define parameters that are important for the operation in the RS485 network. Factory settings of
communication are #33\115200,n,8,2 (address 1 to 247\baud rate 2400 to 115200 b/s, parity,
data bits, stop bit).
Modbus table: with this setting, a Modbus table for measurements and settings is defined. Modbus
addresses for measurements and settings can be compatible with the previous family of
transducers (MTR-2). For a more detailed description, see chapter 7, “Appendix A: Modbus
protocol”, on page 28.
USB Communication
For description of all settings
see Serial Communication, appendix A
. For driver installation,
see the note on page 13. The instrument will establish a USB connection with the PC approx. 5
seconds after physical connection to the USB port.
Settings of connections must reflect actual state, otherwise measurements are
not valid.