Programmable Class 0.2 MC2UP Electrical Size Transducer

DESCRIPTION
On-site fully programmablemulti-output transducer suitable for single phase or three-phase 3-4 wire balanced or unbalanced system. It is suitable also under distorted wave-forms conditions.The multi-output transducer permits to reduce strongly the installation complexity and the relevant costs and it permits to save a lot of space for fitting. Moreover the on-site complete programmability permits to use it for any measuring type requirement and, as a consequence, to semplify and to reduce either the supplies or availability of spare parts. On request it can be fitted with a RS485 serial interface plus Modbus protocol and with a programmable photo-mos output which can be set either as an alarm contact or as a pulse output for remote energy counting.

ON-SITE FULLY PROGRAMMABILITY

These transducers are on-site fully programmable by using a standard USB interface and a remote simple configuration software.
The programmability includes the following function:

• Type (single or three phase, 3 or 4 wires, balanced or unbalanced load)
• Nominal value of inputs (voltage 57÷400V and current 1÷5A with automatic switching of the gains)
• Current and voltage transformer ratios

For each output (indipendent)

• Output type (V or mA)
• Rated output value.
  Eg: 0…+/-1mA (15kΩ), 0…+/-5mA (3kΩ), 0…+/-10mA (1,5kΩ), 0…+/-20mA (750Ω),
  4…20mA (750Ω); 0…+/-1V (>2kΩ); 0…+/-10V (>2kΩ), 2…10V (>2kΩ), etc)
• Measure to be associated to the output, selected from among those available (See table).
• The start and full scale output values (eg. -25…0…100kW; 45…50…55Hz; 0.5C...1...0.5L; etc.)

For alarm output:

• Operating mode (minimum, maximum or a s watch-dog)
• Variable to be monitored
• Threshold level
• Operating delay

Or to retransmit the energy counting:

• Type of energy (active or reactive)
• Weight (eg 1 pulse = ... kWh)

For the serial interface

• Local address
• Communication parameters

ADDITIONAL MEASUREMENTS
In addition to the measurement of the main characteristics of the electricity grid, these transducers calculate and provide ery useful additional information, such as:

• The average current (thermal power)
• The maximum value reached by the thermal current The average current and the maximum value reached by the average current simulating the index black and the red of a bimetal ammeter.
• The average value of active power
• The peak (maximum value reached by the average active power)
• System voltage and current (average voltages and currents).
• Neutral current: obtained by the vector sum of phase currents (does not require an additional CT on the neutral conductor), indicating a poor distribution of loads on three phases and the presence of distorting loads.
• Target power factor: also called D.P.F. (Displacement power factor), indicates the real phase shift between voltage and current introduced by inductive or capacitive loads. The D.P.F. is different from the P.F. (Power factor). The P.F. value is affected by the harmonic distortion and could lead to P.F. corrections even in those cases where the P.F. value is lowered by harmonic distortions and not by unbalanced loads
• THD: Total harmonic distortion, shown as a percentage of the fundamental or RMS value. To prevent high levels of harmonic distortion, but at a very low consumption, would lead to unjustified alarmism, the total harmonic distortion can also be expressed as a percentage of nominal value, setting it in a more proper way.

Wiring diagram

TRMS

The measurement of the main variables (currents and voltages) is performed with the sampling method, which, in its own nature, permits the correct computation of the TRMS even in presence of distorted waveforms, which are more and more usual in modern electrical installations.

INSULATED OUTPUTS

All outputs in addition to the sefety insulation betweenthe measuring inputs and the auxiliary supply, are also insulated from each other: this helps to prevent or solve typical problems such as ground loops or plant masses at different potential between them.

DATA INTERFACE

On request a RS485 serial interface with Modbus RTU protocol is available for interfa-cing the transducers to supervision and energy management systems. on the same RS485 line is possible to wire up to 32 devices (128 with option ¼ unit load). The max line lenght shall be 1200 meters. A particular attention was paid to the optimization of the data transmission with the aim to get a complete picture of the system situation by means of very compact data packa-ges. Anyway it is always possible to choose which type of measurements have to be included in the data transmission.

ALARM OR PULSE OUTPUT

It is available (as option together with the RS485 interface) a photo-MOS programmable output that can be used as an alarm to monitor the operation of a specific measured quantity, or as a pulse for remote energy counting. It is possible to define the operation mode (minimum, maximum or as a watch-dog), the monitored variable, the set point and the delay. Alternatively, it is possible re-transmit the energy to remote units such as counting exter-nal pulses, PLC and so on. The pulse can be programmed directly, eg. 1 pulse = ... kWh, as well as the type of energy (active or reactive).