background image

ENGLISH 4/8

MI003074-E

OPERATING LOGIC

The module measures the following electrical quantities: Vrms, Irms, Watt, VAR, 
VA,  Frequency,  Cos

  and  Active  Energy,  and  provides  the  values  in  the  

corresponding MODBUS registers.
In three-phase environments, measurements given above corresponding to any 
phase are available, other than the three-phase value (except the frequency).
These measurements are rendered in both floating point and normalized format 
(except Frequency and Active energy) between 0..+10000 (-10000 ..+10000 for 
VAR e Cos

). Active energy value is stored in memory and when the instrument is 

switched off, the last value before switching is kept in memory.
The module output can transmit one of the following quantities: Vrms, Irms, Watt, 
cos

 as either a current or voltage value. If the instrument is set for three-phase 

measurements, it transmits automatically the three-phase value of the selected 
measurement. However,  via MODBUS register, the user can choose to transmit 
the measurement corresponding to any phase: A, B, C.
The  user  can  set  through  MODBUS  the  values 

MIN

  and 

MAX

  of  the 

measurement to transmit corresponding to 0% and 100% of the analog output.  
For example, if the signal is transmitted as current 4..20 mA and the quantity to 
transmit is voltage Vrms in the 10..300 V range, (therefore 

MIN=10, MAX=300

), 

then if Vrms measured is 10V, analog output will be 4mA, while if Vrms=300V 
output will be 20mA. In the intermediate points the behaviour is linear. The analog 
output values saturate at approximately 11 V for voltage output and at 22mA for 
current output (analog output clamped at 110 %). 
If network frequency oscillates more than 30 mHz from rated values (50 o 60 Hz), 
it’s  possibile  to  compensate  errors  on  measurements  of  Power  and  Energy 
caused by these variations. This option is selectable via MODBUS register. Vrms 
and Irms measurements are not influenced by these variations.
When  the  module  is  switched  on,  the  appropriate  setting  coefficients  are 
measured (depending on the choice of 50 or 60 Hz frequency). All the settings 
made will be automatically loaded when the module is reset.
NOTE: without load connected to the S203RC-D, only the (displayed) voltage 
and frequency assume a corrected value.

ROGOWSKI’S COIL

Rogowski’s coil have been designed for accurate non-intrusive measurement of 
AC, pulsed DC or complex waveforms. To use in an appropriate way, 
- wrap the ring on the conductor so that the arrow symbol (stamped in the ring) is 
oriented in the same direction of the current in the conductor
- make sure that the connections are performed properly: the white output wire is 
positive (+), the brown wire is the negative (-).

Summary of Contents for S Series

Page 1: ...iguration software please see www seneca it Contents General Specifications Technical Specifications Installation Rules Electrical connections Modbus connection rules DIP switches settings Digital inputs Leds Signallings Factory Settings Contents General specifications Technical features Functioning Rogowski s coil Electrical quantities Electrical connections LEDs signallings Serial interface Case...

Page 2: ...se chosen by specific display or MODBUS registry The module is also distinguished by Communication configurability through software RS485 serial communication with MODBUS RTU protocol maximum 32 nodes Easy wiring of power supply and serial bus by means of the bus housed in the DIN rail High precision 0 5 class Protection against ESD discharge up to 4 kV Measure input insulation 4000 Vac towards al...

Page 3: ...ntal conditions Voltage Consumption 11 40 VDC or 19 28 VAC 50 60 Hz Max 2 5 W Temperature Humidity 10 65 C 30 90 Voltage Output Analog Output 0 10 Vdc 0 5 Vdc Min load resistance 2 k Current Output 0 20 mA 4 20 mA Max load resistance 500 Transmission error Response time 0 1 max range 2 s 10 90 Isolations Insulation voltage 4000 Vac between the input and all the other circuits 1500 Vac between powe...

Page 4: ...A and the quantity to transmit is voltage Vrms in the 10 300 V range therefore MIN 10 MAX 300 then if Vrms measured is 10V analog output will be 4mA while if Vrms 300V output will be 20mA In the intermediate points the behaviour is linear The analog output values saturate at approximately 11 V for voltage output and at 22mA for current output analog output clamped at 110 If network frequency oscil...

Page 5: ...e conductor in a central position with reference to the ring For a correct measurement calibrate the Rogowski s coil write the calibration coefficient to the corresponding Modbus register refer to the user manual or set it using the menu on the display see display programming manual Example if the Rogowski s coil feature is 90 mV 1000 A set the tarature register corresponding to the phase where th...

Page 6: ...9 18 17 16 15 14 13 ZL x x VG A C B 22 21 20 19 18 17 16 15 14 13 N ZL x x x 3 WIRES Three Phase without Neutral VG A C B 22 21 20 19 18 17 16 15 14 13 N ZL x x x VG A C B 22 21 20 19 18 17 16 15 14 13 N ZL x x x There is no insulation between RS485 and the analog output 4 WIRES Three Phase with Neutral Note Connect the shield of the Rogowski s coil at negative so one of the terminals 14 16 18 22 ...

Page 7: ...o the energy counter Imax V R 50 mA Vmax 28V For more informations see the display settings manual For detailed information on RS485 serial interface consult the documentation provided by the website www seneca it in the section Prodotti Serie Z PC MODBUS TUTORIAL SERIAL INTERFACE Digital output 29 30 I R V ANALOG OUTPUT The module provides a programmable analog output in voltage 0 10 Vdc or activ...

Page 8: ...ill help prevent potential negative consequences to the environment and human health which could otherwise be caused by inappropriate disposal of this product The recycling of materials will help to conserve natural resources For more detailed information about the recycling of the product please contact your local city office waste disposal service of the retail store where you purchased this pro...

Reviews: