FAQ – Operational issues SIA-C

SIA-C Dual & Self-powered Overcurrent & Earth Fault Relay


I will store the relays till the moment I really need them, is there any problem with this?

If the relays are not for immediate use, they should be returned to their original packaging, they must be stored in a dust and humidity free environment after the visual inspection has been performed.

Do I have to do any check before the equipment is supplied?

Yes, the following checks:

  • The rated voltage and polarity.
  • The power rating of the CT circuit and the integrity of the connections.
  • The integrity of the earth connection.

I want to recycle an old relay, is this operation dangerous?

Capacitors should be discharged through the external terminals. All electrical power sources should be removed before performing this operation to avoid the risk of electrical discharge.

This product must be disposed of in a safe way. It should not be incinerated or brought into contact with water sources like rivers, lakes, etc…


I have 3 CTs (one for each phase) and the equipment has 4 current inputs, how is the wiring in order to have earth fault protection?

The wiring shall be performed as the connection diagrams of chapter 2.9 in the manual.

I am trying to power the relay with a 24 Vdc auxiliary power supply but it doesn’t work

First of all, ensure that the provided SIA-C relay supports 24 Vdc power supply by checking your SIAC model with the Model Selection Table: SIACxxx3xxxxxxx.

If it is supported, check that the polarity in the terminals is correct: D2 positive and D1 negative.


What is the minimum current that the relay is operative?

The equipment is operative with 0.2 times the secondary rated single-phase current and with 0.1 times the secondary rated three-phase current; in other words, the equipment powers itself with 1 A of single-phase current and with 0.5 A of three-phase current with the SIAC5 models, and the equipment powers itself with 200 mA of single-phase current and with 100 mA of three-phase current with the SIAC1 models.

What is the minimum current that the relay needs for tripping?

The same minimum current that allows the relay be operative.

Although the trip contact is activated, the phase and neutral trip output are not working

Take into account that the minimum current values to active the trip output and signalling outputs are different. To activate the optional outputs (phase trip and neutral trip) it is needed a minimum of 0.330 times the secondary rated single-phase current and a minimum of 0.200 times the secondary rated three-phase current.

Why does the LCD sometimes lights and other times doesn’t?

It is neccssary a current of 0.35xIn (1 phase) or 0.15xIn (3 phase) to activate the backlight. Ensure that your SIAC model has backlight: SIACxxxxxxxxxFx and SIACxxxxxxxxxGx

Why don’t the three LED indicators light?

By default these LEDs indicate the type of power is being used but as they are configurable thanks to the programmable logic (PLC), the configuration must be checked in order to know what signal has each LED associated.

What is the accuracy of the measurement?

Current measurements have an accuracy of 2% on a band of ±20% over the nominal current and 4% over the rest of the range.

Can I communicate with SICom program using rear port ?

Yes, but take into account that the rear port is a RS485 port and requires to be converted to RS232 to your PC. Ensure that the relay is provided with this functionality by checking your SIAC model with the Model Selection Table: SIACxxxxx1xxxxx.

Local and Rear port parameters can be checked maintaining pressed the key “▼”
The default Modbus address for local communication is 1 and 2 for rear communication.

Does SIAC relay meet the requirement of transformer inrush current restraint?

Yes, SIA-C measurement is performed according to the following three steps:

  • Sampling of 16 samples/cycle. Thus the maximum frequency in a sampled signal is 400Hz in the case of 50Hz and 480Hz in the case of 60 Hz, which corresponds with 8th harmonic.
  • Filtering software to eliminate even harmonics: 2, 4, 6 and 8 harmonics. This way it removes the DC component and reduces the effect of exponential component introduced by the inrush current of transformers.
  • RMS on the remaining harmonics, including fundamental, 3, 5 and 7 harmonic.

Which is the consume of the relay when auxiliary power supply is used?

SIA-C consumes approximately 500 mW in normal operation.

What is the pick up time after a startup?

The pickup time is 60 ms for triphasic and nominal current (fast startup) and 120 ms for monophasic and nominal current (fast startup). These values decrease with an increase of the circulating current.

What is the pick up time when the relay is completely started?

The pick up time has a maximum value of 1 cycle (16 ms for 60Hz, 20 ms for 50Hz)


How does 50/51N/G function work? Does the Dial setting affects to the function when the selected Curve is Defined Time?

If the option “Defined time” is selected for the curve setting, the unit behaves like an instantaneous overcurrent unit. In this case, the unit operating time is adjusted by using the parameter “Operating time”. Dial Setting doesn’t affect to the function in this case.

Does the Operating Time setting of 51P/51N/G function affects to the function when a Curve is selected?

When Extremely Inverse, Very Inverse or Inverse curve is selected, the operating time setting does not affect to the function, the applied operating time is calculated from the selected curve.


Which current transformers must I use for this relay?

It will depends on the characteristic of the installation, but the main features that you require to know are:

Frequency (50/60Hz)

Burden 2,5 VA if the transformer is /1 and 5 VA if the transformer is /5

Transformation ratio

Protection Accuracy: it depends on the measurement range you need, i.e. 5P10 will have a 5% accuracy in the range of 10xIn

Do I require specific CTs?

No, this is one of our main advantages, because our relay can work with a very simple and cheap standard CTs, you do not need to buy special ones (as you have to do with other brands). We recommend you to use 3 CTs (one per phase, the neutral can be calculated as a summation of the 3 phases).

What is the maximum current supported continuously?

3 times rated current continuously, 20 times rated current for 10 s and 70 times rated current for 1 s.

Why I get no message in the HMI after a trip occurs when the relay is self powered?

After a trip, the power supply falls and relay restarts, so no message is available in the HMI.

This behaviour is different using auxiliary power supply. In this case, after a trip, a message with the reason of the trip remains in the HMI.

In any case, the magnetic flags remain active showing the last trip that has occurred.

What is the accurate of the events register?

The memory timestamp is accurate to 1 millisecond.

What does a Fault record provide?

Date-time at which the fault started and a list of all events occurred in the equipment during the fault.


Are the events stored in switch on to fault situation?

Yes, the Events and the Fault reports.

Is there any kind of self-diagnostic in the relay?

Yes, diagnostic algorithms are run while the equipment is being started up and continuously when the relay is operating. There is a mechanism of WatchDog, among the different main CPU’s. The loss of activity for any of them would mean the equipment reset, remaining as an event in the memory.

Is there any kind of self-diagnostic in the relay?

Yes, diagnostic algorithms are run while the equipment is being started up and continuously when the relay is operating. There is a mechanism of WatchDog, among the different main CPU’s. The loss of activity for any of them would mean the equipment reset, remaining as an event in the memory.

I did some tests with a relay and some days later I found a wrong date and time, is it broken?

No, RTC keeps the data updated during at least 72 hours without power supply. Charge time for the capacitor is 10 minutes.

We avoid the use of batteries that require a maintenance.

Events and Fault records are stored in a Non-volatile memory, so there won’t be lost of information due to lost of power supply.

What does the PCL consist of?

It is a group of Logical gates (OR, NOR, OR_LACTH, NOR_LACTH, OR_PULSES, AND, NAND, AND_PULSES) that associates binary states to obtain other binary result.

What is default configuration of each output?

The following:

LEDs LED Self-Powered OR4_PULSES Self-power
LED Battery OR4_PULSES Battery
PHYSICAL OUTPUTS Phase Trip AND4 Phase Trip General Trip
Neutral Trip AND4 Neutral Tripa General Trip
Watchdog NOR4 Ready
LOGICAL SIGNAL Reset logical signal Not configured

How can I configure the relay through HMI? And through SICOM?

For HMI configuration, refer to chapter 7 Communication and HMI.

SICOM is an intuitive program that permits configuring the relay with the same parameters as HMI.

How can I latch a digital output configured like trip?

It is necessary to configure the signalling output as trip output and after this configuration if OR4_LACTH is chosen the block of this output is being permited.

I changed the logic configuration of the equipment but it seems that is not working.

If a logic is performed in the relay, it will be applied after a restart.

How can I test that all the components of my relay work properly?

There is a TEST MENU that permits testing each LED, magnetic indicator and digital output. The following key sequence is used to gain access to the test menu: from the main menu, press the keys “◄”, “▼”, and “►” in sequence and then press and hold the “OK” key until the “Test menu” appears on the display. The test menu is accessed by pressing the “OK” key again, and the “▲” and “▼” keys can be used to navigate through the different menu items. Each item can be activated or deactivated by pressing “OK” on it (if the item is deactivated, it is activated by pressing OK; if the item is activated, it is deactivated by pressing “OK”). Press the “C” key to exit the test menu.

May I have to connect the battery unit (KITCOM) for source of supply?

No, the SIAC does not need separate power supply. It’s completely self-powered. Concerning the KITCOM, it is just for the following. When the line drops, if your engineers want to see the events or the reason why the relay has tripped, they only have to connect the Kitcom to the front of the relay. It’s not necessary, it’s just an accessory, the relay WORKS WITHOUT IT. But we find it as an advantage, as it is comfortable to use, not only when the line has tripped and you want to know the events, but also if you want to test the relay. With the Kitcom you can test it without having the relay installed.

I purchased a KITCOM for commissioning but it seems that doesn’t work, how can I confirm this?

First of all, confirm that the 2 batteries of 1,5V are completely charged and when the KITCOM’s switch is activated the green Led is on. If yes, you can check with a multimeter, if there are 12V if you measure between the pins 4 and 7 of the DB9.

Why KITCOM and not an internal battery?

KITCOM is an external complement that allows the users to test the circuit breaker before the transformation center is powered. Some relays manufacturers have the necessity of using internal batteries to log the events and fault reports because they don’t uses non-volatile memory.

FANOX self-powered relays log events and fault reports in non-volatile memory keeping all the information indeed when the relay loses the supply.

If you have an internal battery, you must take care of its maintenance and it is not a real self- powered relay free of maintenance.

Which striker may I use? Is there any limitation?

Although there are a lot of models of strikers in the market, with different trip energies, SIA-C output supplies sufficient power to activate a 24 Vdc and 135 mJ striker. If you have any doubt with your striker, we can do some tests with the same.

Can I use 110Vdc for the trip output?

Yes, but the supported load is restricted. SIAC’s trip output has the following technical characteristics (for coils):


What is the maximum energy that the TCM adapter can supply?

TCM supplies 30 J at 48Vdc, 110Vdc or 220Vdc depends on model

Auxiliary power is not available, will the TCM work?

If TCM has been previously charged, it can operate as a stand alone for up to three days in case of power fault

May I have diferent settings for different CT ratios?

No, the CT ratio parameter belongs to the general setting group and this group has an unique table.


What is the supported voltage of the digital outputs?

These digital outputs, phase trip, neutral trip and Watchdog , are used to signal and the supported voltages are 220 Vdc – 1 A (30 W max) and 250 Vac – 1 A (62,5 VA max)


I am not able of communicating with SICom program. What’s wrong?

It is necessary to check the following points:

  • Ensure that the port you are trying to use of your PC is available (check it in the Control Panel->Hardware->Device Manager->Ports (COM and LPT)
  • It is required that the crossover serial cable is in good state.
    The DB-9 male connector of the serial cable has to be well connected to the relay.
  • The PC earth should be connected to the same earth as the relay to avoid communication problems.
  • SICOM communication parameters are correct: COM port and Modbus address (default front Modbus address is 1).

I have changed the Modbus address of my relay, should I change it in the SICom?

Yes, before pressing the Start button of the SICom, it is necessary changing the Modbus Address in: File->Options->Options for Communication

I can’t find de SICom CD, how can I get it?

Fanox provides their customers with an internet link to SICom program. You will only need a PC and an internet connection.

The link to SICom program is: http://fanox.blob.core.windows.net/sicom/publish.htm

Why some features of SICom appear dimmed?

SICom only permits the features of the relay that is communicating with. i.e. If the relay does not support commands, the executing commands feature, will be dimmed.

Can I inherit the settings from one relay to another?

SICom allows saving the existing settings of a relay in a file. This file can be loaded to another protection relay.

How many relays can be updated at the same time?

SICom program allows communicating just one relay for each instance of the program. If the PC is provided with multiple serial ports, it is possible running so many instances as COM ports has the PC to communicate with multiple relays.

Does the SICom require to be updated?

When an internet connection is available, SICom automatically checks if a new revision is available, in positive case, it updates itself.

What do yellow triangles mean in the States screen? And the coloured bulbs?

A yellow triangle appears next to the signal that is activated. A red bulb indicates that there is a signal activated inside the function. If there is no signal activated, the bulb will remains green.

How may I configure my SCADA to communicate with SIA-C relay?

You have to take into account these considerations:

The RS485 port output has three terminals (+,- and GND), located on the rear of the equipment. The protocol that is used is Modbus RTU (19200 -8bit – no parity – 1 stop bit).

The protocol map and documentation that are used are attached in an appendix to the manual.

To minimise communication errors as a result of noise, the use of a stranded and shielded cable is recommended for the physical connection. All of the + terminals on one side, and all of the – terminals on the other must be connected together in order to make the connection.

If a 3 strand cable is used for communication, the GND terminals must be connected to the earth cable.

If a 2 strand cable is used for communication, the GND terminals must be connected to the shielding. The shielding must be connected to the GND at only one point to avoid circular currents.

How can I check that the Modbus integration in my SCADA is correct?

It can be checked by doing the following example:

Writing the access password “5555” to equipment no. 1

Captura de pantalla 2015-05-14 a la(s) 01.32.21

SIA will reply OK:

Captura de pantalla 2015-05-14 a la(s) 01.34.00

The trip bistable of the front of my relay remains active although the trip condition has disappeared, is this normal?

Yes, the indicators remain in position even when the equipment looses power, so that the maintenance service can see the cause of the trip even through the equipment is not powered.

Once they have been activated, it is necessary to manually reset them by pressing the “RESET” button.

I have Windows XP in my laptop, can I use SICom program with it?

The SIcom program, works with the Windows® 2000/XP/7 and Windows 8 operating systems.

How can I limit the access to different operators ?

There is a Users identification system with different access level. Depending on the access level, it may or may not be possible to perform the operations shown on the table below.

Captura de pantalla 2015-05-14 a la(s) 01.36.25

How many passwords are possible?

Four passwords. Their associated levels of access are set up when the equipment is configured using the SIcom program. By default, the equipment is programmed with the following passwords and their associated levels:

Captura de pantalla 2015-05-14 a la(s) 01.40.20

How can I limit the access to different operators ?

There is a Users identification system with different access level. Depending on the

I have 2 protection relays, how can I check that they both have the same versions?

The equipment versions menu can be accessed from the standby mode screen by pressing and maintaining pressed the key “▲”. This displays the software versions of the relay processors.

Captura de pantalla 2015-05-14 a la(s) 01.42.03

How can I calibrate the equipment?

With SIAC model relay, there is no need for additional external calibration of the relay. It is calibrated in our factory and the measurement is maintained continuously during life time of the relay. This way, we can avoid the customers the inconveniences generated for this matter with other relays. With factory calibration, the accuracy of the relay is ±2% at ±20%xIn / ±4% in the rest of the range.

The only thing that the user must do is to adjust the relay protection function 50/51P & 50/51N according to his requirements of installation. After this, the relay is completely ready to work and protect (obviously, after the wiring, of course).