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3.3 Input and output signals

Version 11.3 by Admin on 2024/11/21 16:04

3.3.1 Input signals

The BMS Main 2.x board has 4 discrete inputs of the "dry contact" type. For each discrete input, its purpose and the inversion requirement are specified. The following discrete input assignment options are supported:

  • no signal;
  • signal from battery cover;
  • charger connected;
  • power up/down request;
  • inhibit charging;
  • inhibit discharging;
  • CH contactor feedback;
  • DCH contactor feedback;
  • Insulation status;
  • Charge request;
  • Precharge request;
  • Discharge request;
  • PCH contactor feedback;
  • CH/DCH contactor feedback;
  • Main contactor feedback.

If the "Signal from the battery cover" assignment is selected, the discrete input is used to monitor the state of the battery cover (see section Battery cover protection).

if the "Charger connected" assignment is selected, the discrete input is involved in the algorithms of charge and discharge control (see sections Charge control and Discharge control).

If the "Power up/down request" assignment is selected, the discrete input is involved in the algorithms of opening the charging and discharging relays and sending acknowledgment of power down to the external equipment (see sections Charge control and Discharge control).

If the “Inhibit charging” assignment is selected, the discrete input is used to open the charging relay.

If the “Inhibit discharging” assignment is selected, the discrete input is used to open the discharging relay.

If the “CH contactor feedback”, “DCH contactor feedback”, “PCH contactor feedback”, “CH/DCH contactor feedback” or “Main contactor feedback” assignment is selected, the discrete input is involved in monitoring the corresponding contactor’s feedback signal (see section Contactor feedback check).

If the “Charge request”, “Precharge request” or “Discharge request” assignment is selected, the discrete input is used to control opening the corresponding contactor (see sections Charge control and Discharge control).

If the “Insulation status” assignment is selected, the discrete input is used to monitor a signal from an external insulation monitoring device (see section Insulation monitoring).

BMS Main 2.x board has 4 analog inputs for connecting current, temperature and humidity sensors. Assignment of analog inputs must be selected as follows:

  • Analog Input #1 – Current sensor;
  • Analog Input #2 – No input / Current sensor reference line / Current sensor (2nd range) (see note);
  • Analog Input #3 – No input / Temperature sensor / Current sensor (AUX);
  • Analog Input #4 – No input / Humidity sensor / Current reference line (AUX) / Current sensor (2nd range) (AUX).

Important: the connection of an additional current sensor (AUX) is possible for special hardware revision of the BMS Main 2.x board. Using an additional current sensor is possible in the configuration when BMS Main serves two galvanically isolated cell series (see section Series balancing).

Warning: reassignment of analog inputs is unacceptable.

Note: The default setting for Analog input #2 is "No signal". If it is necessary to use a current sensor with an additional zero level signal, set the "Current sensor reference line" assignment.

 To configure the input discrete and analog signals, select the menu "Signals → Input signals":

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Input signals section

 The order of the numbering of the discrete and analog inputs corresponds to the order of the numbering on the board.

In this section:

  • Discrete inputs:
    • No input;
    • Battery cover – a signal from the battery cover trailer;
    • Charger connected – a signal from the charger connector;
    • Power up/down request – a signal from the external power monitor which is used for proper powering BMS up or down;
    • Inhibit charging – a command to open the charging relay;
    • Inhibit discharging – a command to open the discharging relay;
    • CH contactor feedback – a feedback signal from the charging contactor;
    • DCH contactor feedback – a feedback signal from the discharging contactor;
    • Insulation status – a signal from an external insulation monitoring device;
    • Charge request – a request for closing the charging contactor;
    • Precharge request – a request for closing the precharging contactor;
    • Discharge request – a request for closing the discharging contactor;
    • PCH contactor feedback – a feedback signal from the precharging contactor;
    • CH/DCH contactor feedback – a feedback signal from the charging/discharging contactor;
    • Main contactor feedback – a feedback signal from the main contactor.
  • Analog inputs:
    • No input;
    • Current sensor;
    • Current zero level;
    • Temperature sensor;
    • Humidity sensor;
    • Current sensor (AUX) – additional current sensor for measuring current in a series of cells;
    • Current zero level (AUX) – zero level bus for additional current sensor.

3.3.2 Current sensor

After selecting the assignment of the analog inputs, you need to configure the parameters of the sensors connected to the board.

To configure the current sensor parameters, select the menu "Signals → Current sensor":

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Current sensor settings

In the «Primary sensor» и «Auxiliary sensor» sections:

  • Sensor type – drop-down menu with supported sensor types;
  • Nominal current – rated current of the sensor according to the datasheet, А;
  • Sensitivity – sensitivity of the current sensor according to the datasheet, V / Inominal.;
  • Zero level – level "0A" of the current sensor, V;
  • Multiply the charging current (experimental) – experimental flag for scaling the charging current by given multiplier;
  • Multiplier – charging current multiplier;

In the «Options» section:

  • Calibrate sensor on startup – calibration flag (zero level setting) of the current sensor when the board is started;
  • Calibration time – calibration time of the current sensor, second;
  • System consumption (current offset) – consumption of the BMS system from the battery, A; This setting is used to adjust the current sensor;
  • Set sensor zero level – command set the zero level of the current sensor (used for service purposes).

If the "Sensor type" is selected, the “Nominal current” and “Sensitivity” fields are automatically filled.
If the "Sensor type" has no necessary preset, the “Nominal current” and “Sensitivity” parameters must be manually entered.

Calibration of the current sensor (“Calibrate sensor on startup” flag) is necessary if the sensor does not have a reference line (zero level signal).

3.3.3 Current shunt sensor

To configure the shunt current sensor parameters, select the menu "Signals → Current shunt sensor":

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Shunt sensor settings

In this section:

  • Settings:
  • Enable – a flag to start interaction with BMS Current Sensor (if interaction is enabled then BMS doesn’t use Hall-Effect current sensor which settings are described in the menu "Signals → Current sensor");
  • Node ID – an address of BMS Current Sensor in CANopen network;
  • Dispatch timeout – timeout of dispatching packages from BMS Current Sensor (if no data is being received from current sensor during this time, the “Shunt offline” flag is set), millisecond;
  • Zero level threshold – T0 level, A (if module of instantaneous current (II) which is received from shunt sensor is lower than T0, BMS will assume that current flowing through the battery is zero);
  • Mean level threshold – TM level, A (if module of instantaneous current (II) which is received from shunt sensor is between TM and T0, BMS will use mean value of current IM; if II is greater than TM, BMS will use instantaneous value of current II);
  • Invert – a flag to invert current values;
  • Sensor state:
    • Online – a flag showing that the communication with the BMS Current Sensor is established;
    • Errors – a list of internal errors of the shunt sensor;
    • Current – an instantaneous value of current measured by the BMS Current Sensor, A (measuring frequency is 50 Hz);
    • Current (mean) – a mean value of current measured by the BMS Current Sensor, A (the value is calculated as an average of 100 consistent measurements);
    • Temperature – a temperature of the shunt sensor, °C. 

3.3.4 Temperature sensor

To configure the temperature sensor parameters, select the menu "Signals → Temperature sensor":

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Temperature sensors settings

In this section:

  • Type – type of temperature sensors.
  • Mask - 

Note: Temperature sensors connected to the BMS Main 2.x and BMS Logic boards must be the same type.

3.3.5 Humidity sensor

To set the humidity sensor parameters, select the menu "Signals → Humidity sensor":

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Humidity sensor settings

 In this section:

  • Type – type of the humidity sensor.

3.3.6 Output signals

The BMS Main 2.x board has 4 discrete outputs. For each discrete output, its purpose and inversion requirement are specified. The following discrete output assignment options are supported:

  • No output;
  • Low SOC;
  • Hgh battery charge current;
  • Cooler;
  • Heater;
  • Allow charging;
  • Precharging;
  • Acknowledgement of power down;
  • Power up.

If the "Low SOC" assignment is selected, the output indicates the low battery charge level (see section Low SOC signal).

If the "High battery charge current" assignment is selected, the output indicates that the charging current exceeds the predefined value (see section High charging current signal).

If the "Cooler" assignment is selected, the output indicates the overheating of the battery (see section Temperature protection).

If the "Heater" assignment is selected, the output indicates the low battery temperature signal (see section Temperature protection).

If the "Allow charging" assignment is selected, the output is used to give the charger the allowance to charge the battery (see section Charge control).

If the "Precharging" assignment is selected, the output is used to charge the capacitive load (see section Discharge control).

If the "Acknowledgement of power down" assignment is selected, the output is used to acknowledge power down of the BMS. Acknowledgement is outputted when the charge and discharge relays have been opened on power down request (see sections Charge control and Discharge control).

If the "Power up" assignment is selected, the output is used to indicate the power status of BMS (see section Power down control).

The BMS Main 2.x board has 4 solid-state relays (#1 and #2 of them are bipolar, and the #3 and #4 are unipolar). For each relay, its purpose and inversion requirement are specified. The following relay assignment options are supported:

  • No relay;
  • Charging;
  • Discharging;
  • Allow charging;
  • Cooler;
  • Heater;
  • Precharging;
  • Balancing series 1;
  • Balancing series 2;
  • Discharging (AUX);
  • Main contactor;
  • Power up.

If the "Charging" assignment is selected, the relay is used to charge the battery (see section Charge control).

If the "Discharging" assignment is selected, the relay is used to connect battery to the load (see section Discharge control).

If the "Allow charging" assignment is selected, the relay is used to give the charger an allowance to charge the battery (see section Charge control).

If the "Cooler" assignment is selected, the relay receives a signal indicating overheating of the battery (see section Temperature protection) or the signal "Cooler" (see section Cooler control).

If the "Heater" assignment is selected, a low battery temperature signal is outputted to the relay (see section Temperature protection) or a signal "Heater" (see section Heater control).

If the "Precharging" assignment is selected, the relay is used to charge the capacitive load (see section Discharge control).

If the "Balancing series 1" assignment is selected, the relay is used to connect a balancing resistor to the cell series 1 (see section Series balancing).

If the "Balancing series 2" assignment is selected, the relay is used to connect a balancing resistor to the cell series 2 (see section Series balancing).

If the "Discharging (AUX)" assignment is selected, the relay is used to power external equipment (see section Powering external equipment).

If the "Main contactor" assignment is selected, the relay is used to close the main contactor in the common (minus) power bus.

If the "Power up" assignment is selected, the relay is used to close the contactor in the BMS Main power bus.

To configure output discrete signals and relays, select the menu "Signals → Output signals":

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Output