Metering and Monitoring Functions

Description

The LTMR controller measures line currents and provides the value of each phase in amperes and as a percentage of Full Load Current (FLC).

The line currents function returns the rms value in amperes of the phase currents from the three CT inputs:

• L1: phase 1 current

• L2: phase 2 current

• L3: phase 3 current

The LTMR controller performs true rms calculations for line currents up to the seventh harmonic.

Single-phase current is measured from L1 and L3.

Line Current Characteristics

The line currents function has the following characteristics:

Line Current Ratio

The L1, L2, and L3 current ratio parameter provides the phase current as a percentage of FLC.

Line Current Ratio Formulas

The line current value for the phase is compared to the FLC parameter setting, where FLC is FLC1 or FLC2, whichever is active at that time.

Line Current Ratio Characteristics

The line current ratio function has the following characteristics:

Description

The LTMR controller measures ground currents and provides values in Amperes and as a percentage of FLCmin.

• The internal ground current (Igr∑) is calculated by the LTMR controller from the three line currents measured by the load current transformers. It reports 0 when the current falls below 10% of FLCmin.

• The external ground current (Igr) is measured by the external ground current sensor connected to Z1 and Z2 terminals.

Configurable Parameters

The control channel configuration has the following configurable parameter settings:

External Ground Current Formula

The external ground current value depends on the parameter settings:

Ground Current Characteristics

The ground current function has the following characteristics:

Ground Current Ratio

The Ground Current Ratio parameter provides the ground current value as a percentage of FLCmin.

Ground Current Ratio Formulas

The ground current value is compared to FLCmin.

Ground Current Ratio Characteristics

The ground current ratio function has the following characteristics:

Description

The LTMR controller calculates average current and provides the value for phase in amperes and as a percentage of FLC.

The average current function returns the rms value of the average current. It returns to 0 when the average current is below 20% of FLCmin.

Average Current Formulas

The LTMR controller calculates the average current using the measured line currents. The measured values are internally summed using the following formula:

Average Current Characteristics

The average current function has the following characteristics:

Average Current Ratio

The Average Current Ratio parameter provides the average current value as a percentage of FLC.

Average Current Ratio Formulas

The average current value for the phase is compared to the FLC parameter setting, where FLC is FLC1 or FLC2, whichever is active at that time.

Average Current Ratio Characteristics

The average current ratio function has the following characteristics:

Description

The current phase imbalance function measures the maximum percentage of deviation between the average current and the individual phase currents.

Formulas

The current phase imbalance measurement is based on imbalance ratio calculated from the following formulas:

Characteristics

The line current imbalance function has the following characteristics:

Description

The thermal capacity level function uses two thermal models to calculate the amount of thermal capacity used: one for copper stator and rotor windings of the motor and the other for the iron frame of the motor. The thermal model with the maximum utilized capacity is reported.

This function also estimates and displays:

• The time remaining before a thermal overload trip is triggered (refer to Time to Trip), and

• The time remaining until the trip condition is cleared after a thermal overload trip has been triggered (refer to Minimum Wait Time).

Trip Current Characteristics

The thermal capacity level function uses one of the following selected trip current characteristics (TCCs):

• Definite time

• Inverse thermal (factory setting)

Thermal Capacity Level Models

Both copper and iron models use the maximum measured phase current and the Motor Trip Class parameter value to generate a non-scaled thermal image. The reported thermal capacity level is calculated by scaling the thermal image to FLC.

Thermal Capacity Level Characteristics

The thermal capacity level function has the following characteristics:

Description

The motor temperature sensor function displays:

• The resistance value in ohms measured by a PTC or NTC resistance temperature sensor.

• The temperature value in °C or °F measured by a PT100 temperature sensor.

Refer to the product documentation for the specific temperature sensor being used. One of four types of temperature sensors can be used:

• PTC Binary

• PT100

• PTC Analog

• NTC Analog

Characteristics

The motor temperature sensor function has the following characteristics:

Description

The frequency function provides the value measured based on the line voltage measurements. If the frequency is unstable (+/– 2 Hz variations), the value reported is 0 until the frequency stabilizes.

If no LTME expansion module is present, the frequency value is 0.

Characteristics

The frequency function has the following characteristics:

Description

The line-to-line voltages function provides the rms value of the phase-to-phase voltage (V1 to V2, V2 to V3, and V3 to V1):

• L1-L2 voltage: phase 1 to phase 2 voltage

• L2-L3 voltage: phase 2 to phase 3 voltage

• L3-L1 voltage: phase 3 to phase 1 voltage

The expansion module performs true rms calculations for line-to-line voltage up to the seventh harmonic.

Single phase voltage is measured from L1 and L3.

Characteristics

The line-to-line voltages function has the following characteristics:

Description

The line voltage imbalance function displays the maximum percentage of deviation between the average voltage and the individual line voltages.

Formulas

The line voltage imbalance calculated measurement is based on the following formulas:

Characteristics

The line voltage imbalance function has the following characteristics:

Description

The LTMR controller calculates average voltage and provides the value in volts. The average voltage function returns the rms value of the average voltage.

Formulas

The LTMR controller calculates average voltage using the measured line-to-line voltages. The measured values are internally summed using the following formula:

Characteristics

The average voltage function has the following characteristics:

Description

The power factor function displays the phase displacement between the phase currents and phase voltages.

Formula

The Power Factor parameter (also called cosine phi or cos ϕ) represents the absolute value of the ratio of Active Power to Apparent Power.

The following diagram displays an example of the average rms current sinusoidal curve lagging slightly behind the average rms voltage sinusoidal curve, and the phase angle difference between the two curves:

After the phase angle (ϕ) is measured, the power factor can be calculated as the cosine of the phase angle (ϕ)-the ratio of side a (Active Power) over the hypotenuse h (Apparent Power):

Characteristics

The power factor function has the following characteristics:

Description

The calculation of the active power and reactive power is based on the:

• Average rms phase voltage of L1, L2, L3

• Average rms phase current of L1, L2, L3

• Power factor

• Number of phases

Formulas

Active power, also known as true power, measures average rms power. It is derived from the following formulas:

The reactive power measurement is derived from the following formulas:

Characteristics

The active and reactive power functions have the following characteristics:

Description

The active and reactive power consumption functions display the accumulated total of the active and reactive electrical power delivered, and used or consumed by the load.

Characteristics

The active and reactive power consumption functions have the following characteristics:

Description

The LTMR controller detects and records trips that are internal to the device itself. Internal trips can be either major or minor. Major and minor trips can change the state of output relays. Cycling power to the LTMR controller may clear an internal trip.

When an internal trip occurs, the Controller Internal Trip parameter is set.

Major Internal Trips

During a major trip, the LTMR controller is unable to reliably execute its own programming and can only attempt to shut itself down. During a major trip, communication with the LTMR controller is not possible. Major internal trips include:

• Stack overflow trip

• Stack underflow trip

• Watchdog time-out

• Firmware checksum detected error

• CPU detected error

• Internal temperature trip (at 100 °C/212 °F)

• RAM test detected error

Minor Internal Trips

Minor internal trips indicate that the data being provided by the LTMR controller is unreliable and protection could be compromised. During a minor trip, the LTMR controller continues to attempt to monitor status and communications, but does not accept any start commands and Custom Logic functions are halted. During a minor trip condition, the LTMR controller continues to detect and report major trips, but not additional minor trips. Minor internal trips include:

• Internal network communications trip

• EEPROM detected error

• A/D out of range detected error

• Reset button stuck

• Internal temperature trip (at 85 °C/185 °F)

• Invalid configuration detected error (conflicting configuration)

• Detected improper logic function action (for example, attempting to write to a read-only parameter)

Description

The LTMR controller monitors its Controller Internal Temperature, and reports alarm, minor trip, and major trip conditions. Trip detection cannot be disabled. Alarm detection can be enabled or disabled.

The controller retains a record of the highest attained internal temperature.

Characteristics

The Controller Internal Temperature measured values have the following characteristics:

Parameters

The Controller Internal Temperature function includes one editable parameter:

The Controller Internal Temperature function includes the following fixed alarm and trip thresholds:

An alarm condition ceases when LTMR Controller Internal Temperature falls below 80 °C (176 °F).

Block Diagram

T Temperature

T > 80 °C (176 °F) Fixed alarm threshold

T > 85 °C (185 °F) Fixed minor trip threshold

T > 100 °C (212 °F) Fixed major trip threshold

Maximum Internal Controller Temperature

The Controller Internal Temperature Max parameter contains the highest internal temperature, expressed in °C, detected by the LTMR controller’s internal temperature sensor. The LTMR controller updates this value whenever it detects an internal temperature greater than the current value.

The maximum internal temperature value is not cleared when factory settings are restored using the Clear All Command, or when statistics are reset using a Clear Statistics Command.

Description

The LTMR controller performs diagnostic tests that detect and monitor the proper functionality of control commands.

There are four control command diagnostic functions:

• Start Command Check

• Run Check

• Stop Command Check

• Stop Check

Parameter Settings

All four diagnostic functions are enabled and disabled as a group. The configurable parameter settings are:

Start Command Check

The Start Command Check begins after a Start command, and causes the LTMR controller to monitor the main circuit to ensure that current is flowing.

• The Start Command Check reports a Start Command trip or alarm if current is not detected after a delay of 1 second.

• The Start Command Check condition ends if the motor is in Start or Run state (lavg > 20% FLC) at the one second delay point, then begins the Run Check.

Run Check

The Run Check causes the LTMR controller to continuously monitor the main circuit to ensure current is flowing.

• The Run Check reports a trip or alarm if average phase current is not detected for longer than 0.5 seconds without a Stop command.

• The Run Check ends when a Stop command executes.

Stop Command Check

The Stop Command Check begins after a Stop command, and causes the LTMR controller to monitor the main circuit and ensure that no current is flowing.

• The Stop Command Check reports a trip or alarm if current is detected after a delay of 1 second.

• The Stop Command Check ends if the LTMR controller detects that the current is equal or less than 5% of FLCmin.

Stop Check

The Stop Check causes the LTMR controller to continuously monitor the main circuit to ensure that no current is flowing.

• The Stop Check reports a Stop Check trip or alarm if average phase current is detected for longer than 0.5 seconds after a Stop command.

• The Stop Check condition ends when a Run command executes.

Timing Sequence

The following diagram is an example of the timing sequence for the Start Command Check and Stop Command Check:

1 Normal operation

2 Trip or alarm condition

3 The LTMR controller monitors the main circuit to detect current

4 The LTMR controller monitors the main circuit to detect no current

5 The LTMR controller reports a Start Command Check trip and/or alarm if current is not detected after 1 second

6 The LTMR controller reports a Stop Command Check trip and or alarm if current is detected after 1 second

The following diagram is an example of the timing sequence for the Run Check and Stop Check:

1 Normal operation

2 Trip or alarm condition

3 After the motor enters the run state, the LTMR controller continuously monitors the main circuit to detect current until a Stop command is given or the function is disabled

4 The LTMR controller continuously monitors the main circuit to detect no current until a Start command is given or the function is disabled

5 The LTMR controller reports a Run Check trip and/or alarm if the current is not detected for longer than 0.5 seconds without a Stop command

6 The LTMR controller reports a Stop Check trip or alarm if the current is detected for longer than 0.5 seconds without a Start command

7 No current flowing for less than 0.5 seconds

8 Current flowing for less than 0.5 seconds

Description

The LTMR controller checks external wiring connections and reports a trip when it detects incorrect or conflicting external wiring. The LTMR controller can detect four wiring errors:

• CT Reversal Detected Error

• Phase Configuration Detected Error

• Motor Temperature Sensor Wiring Detected Errors (short-circuit or open-circuit)

If LTMR controller is connected on the left port of LTME expansion module, the frequency measurement will be wrong. Hence, it is advised to use the LTMCC004 connecting jumper to avoid trips.

Enabling Trip Detection

Wiring diagnostics are enabled using the following parameters:

CT Reversal Detected Error

When individual external load CTs are used, they must all be installed in the same direction. The LTMR controller checks the CT wiring and reports a detected error if it detects one of the current transformers is wired backwards when compared to the others.

This function can be enabled and disabled.

Phase Configuration Detected Error

The LTMR controller checks all three motor phases for On Level current, then checks the Motor Phases parameter setting. The LTMR controller reports a detected error if it detects current in phase 2 if the LTMR controller is configured for single-phase operation.

This function is enabled when the LTMR controller is configured for single-phase operation. It has no configurable parameters.

Motor Temperature Sensor Detected Errors

When the LTMR controller is configured for motor temperature sensor protection, the LTMR controller provides short-circuit and open-circuit detection for the temperature sensing element.

The LTMR controller signals a detected error when calculated resistance at the T1 and T2 terminals:

• Falls below the fixed short-circuit detection threshold (trip code = 34), or

• Exceeds the fixed open-circuit detection threshold (trip code = 35).

The trip must be reset according to the configured Reset Mode: manual, automatic, or remote.

Short-circuit and open-circuit detection thresholds have no trip time delay. There are no alarms associated with the short-circuit and the open-circuit detection.

Short-circuit and open-circuit detection of the motor temperature sensing element is available for all operating states.

This protection is enabled when a temperature sensor is employed and configured, and cannot be disabled.

The motor temperature sensor function has the following characteristics:

The fixed thresholds for the open-circuit and short-circuit detection functions are:

Description

The LTMR controller calculates a checksum of parameters based on all configuration registers. The EEPROM detected error code (64) is reported.

Description

The LTMR controller monitors communication through:

• The network port

• The HMI port

Network Port Parameter Settings

The LTMR controller monitors network communication creates both a trip and an alarm report when the network communications are lost.

• On LTMR Ethernet controllers configured with EtherNet/IP or Modbus/TCP communication protocol, the communication loss is detected if no communication exchanges occurred with the Primary IP for a time period equal to, or longer than, the network port communication loss timeout. Primary IP must be configured to allow detection of the communication loss.

• On LTMR Modbus controllers, the communication loss is detected if no communication exchanges occurred for a time period equal to, or longer than, the network port comm loss timeout.

• On LTMR PROFIBUS DP, CANopen, or DeviceNet controllers, the communication loss is detected as part of the protocol management, without specific adjustable parameters.

The network port communications have the following configurable settings:

HMI Port Parameter Settings

The LTMR controller monitors HMI port communications and reports both an alarm and a trip if no valid communication has been received by the HMI port for longer than 7 seconds.

The HMI port communication has the following fixed and configurable settings:

Fallback Condition

When the communication between the LTMR controller and either the network or the HMI is lost, the LTMR controller is in a fallback condition. When the communication recovers, the fallback condition is no longer applied by the LTMR controller.

The behavior of logic outputs O.1 and O.2 when the LTMR controller is in fallback condition is determined by:

• The operating mode (refer to Operating Modes).

• The Network Port Fallback Setting and HMI Port Fallback Setting parameters.

Fallback setting selection can include:

The following table indicates which fallback options are available for each operating mode:

Description

When a thermal overload condition exists, the LTMR controller reports the time to trip before the trip occurs in the Time To Trip parameter.

When the LTMR controller is not in a thermal overload condition, to avoid the appearance of being in a trip state, the LTMR controller reports the time to trip as 9999.

If the motor has an auxiliary fan and the Motor Aux Fan Cooled parameter has been set, the cooling period is four times shorter.

Characteristics

The time to trip function has the following characteristics:

Description

The LTMR controller checks the Load CT parameters set in configuration mode.

An LTMR configuration trip is detected when the Load CT Primary, Load CT Secondary, and Load CT Multiple Passes parameters are not valid, and generates a System and Device Monitoring Trip. The trip condition is cleared once the parameters are correct. The LTMR controller remains in configuration mode as long as the parameters are not valid.

Description

The LTMR controller checks the presence of the LTME expansion module. Its absence generates a System and Device Monitoring Trip.

LTME Configuration Trip

LTME configuration trip:

• If LTME based protection trips are enabled but no LTME expansion module is present, this will cause an LTME configuration trip.

• It does not have any delay setting.

• The trip condition clears when no protection trip requiring an LTME is enabled, or when the LTMR has been power-cycled with an appropriate LTME being present.

LTME Configuration Alarm

LTME configuration alarm:

• If LTME based protection alarms are enabled but no LTME expansion module is present, this will cause an LTME configuration alarm.

• The alarm clears when no protection alarm requiring an LTME is enabled, or when the LTMR has been power-cycled with an appropriate LTME being present.

Description

The LTMR controller has an external trip feature, which detects if an error happened on an external system linked to it.

An external trip is triggered by setting a bit in the custom logic command register 1 (see following table). This external trip sets the controller into a trip state based on different parameters in the system.

An external trip can be reset only by clearing the external trip bit in the register.

External Trip Parameter Settings

Detecting Alarms

If an alarm detection function is enabled, the LTMR controller detects an alarm immediately when the monitored value rises above, or falls below, a threshold setting.

Detecting Trips

Before the LTMR controller detects a trip, certain preconditions must exist. These conditions can include

• The trip detecting function must be enabled,

• A monitored value (for example, current, voltage, or thermal resistance) must rise above, or fall below, a threshold setting,

• The monitored value must remain above or below the threshold setting for a specified time duration.

Counters

When a trip is detected, the LTMR controller increments at least two counters:

• A counter for the specific trip, and

• A counter for all trips.

When an alarm is detected, the LTMR controller increments a single counter for all alarms. However, when the LTMR controller detects a thermal overload alarm, it also increments the thermal overload alarms counter.

A counter contains a value from 0 to 65,535 and increments by a value of 1 when a trip, alarm, or reset event is detected. A counter stops incrementing when it reaches a value of 65,535.

When a trip is automatically reset, the LTMR controller increments only the auto-resets counter. Counters are saved on power loss.

Clearing Counters

All trip and alarm counters are reset to 0 by executing the Clear Statistics Command or Clear All Command.

Description

The Trips Count parameter contains the number of trips that have occurred since the Clear All Statistics Command last executed.

The Trips Count parameter increments by a value of 1 when the LTMR controller detects any trip.

Description

The Alarms Count parameter contains the number of alarms that have occurred since the Clear All Statistics Command last executed.

The Alarms Count parameter increments by a value of 1 when the LTMR controller detects any alarm.

Description

The Auto-Reset Count parameter contains the number of times the LTMR controller unsuccessfully attempted to auto-reset a trip. This parameter is used for the three auto-reset trip groups.

If an auto-reset attempt is successful (defined as the same trip not recurring within 60 s), this counter is reset to zero. If a trip is reset either manually or remotely, the counter is not incremented.

For information on trip management, refer to Trip Management and Clear Commands.

Protection Trip Counts

Protection trip counters include:

• Current Phase Imbalance Trips Count

• Current Phase Loss Trips Count

• Current Phase Reversal Trips Count

• Ground Current Trips Count

• Jam Trips Count

• Long Start Trips Count

• Motor Temp Sensor Trips Count

• Over Power Factor Trips Count

• Overcurrent Trips Count

• Overpower Trips Count

• Overvoltage Trips Count

• Thermal Overload Trips Count

• Under Power Factor Trips Count

• Undercurrent Trips Count

• Underpower Trips Count

• Undervoltage Trips Count

• Voltage Phase Imbalance Trips Count

• Voltage Phase Loss Trips Count

• Voltage Phase Reversal Trips Count

Protection Alarm Counts

The Thermal Overload Alarms Count parameter contains the total number of alarms for the thermal overload protection function.

When any alarm occurs, including a thermal overload alarm, the LTMR controller increments the Alarms Count parameter.

Description

A Diagnostic Trip occurs when the LTMR controller detects any of the following control command detected errors:

• Start Command Check detected errors

• Stop Command Check detected errors

• Stop Check detected errors

• Run Check detected errors

For information on these control command functions, refer to Control Command Trip Diagnostic.

Description

The Wiring Trips Count parameter contains the total number of the following wiring trips that have occurred since the Clear Statistics Command last executed:

• Wiring Trip, which is triggered by a:

  • CT Reversal Detected Error

  • Phase Configuration Detected Error

  • Motor Temperature Sensor Wiring Detected Error

• Voltage Phase Reversal Trip

• Current Phase Reversal Trip

The LTMR controller increments the Wiring Trips Count parameter by a value of 1 each time any one of the above three trips occurs. For information on detected connection errors and related trips, refer to Wiring Trips.

Description

Trips detected for the following communication functions:

Description

Trips detected for the following internal trips:

Trip History

The LTMR controller stores a history of LTMR controller data that was recorded at the time of the last five trips. Trip n-0 contains the most recent trip record, and trip n-4 contains the oldest retained trip record.

Each trip record includes:

• Trip Code

• Date and Time

• Value of Settings

  • Motor Full Load Current Ratio (% of FLCmax)

• Value of Measurements

  • Thermal Capacity Level

  • Average Current Ratio

  • L1, L2, L3 Current Ratio

  • Ground Current Ratio

  • Full Load Current Max

  • Current Phase Imbalance

  • Voltage Phase Imbalance

  • Power Factor

  • Frequency

  • Motor Temp Sensor

  • Average Voltage

  • L3-L1 Voltage, L1-L2 Voltage, L2-L3 Voltage

  • Active Power

Description

The LTMR controller tracks motor starts and records the data as a statistic that can be retrieved for operational analysis. The following statistics are tracked:

• Motor Starts Count

• Motor LO1 Closings Count (logic output O.1 starts)

• Motor LO2 Closings Count (logic output O.2 starts)

The Clear Statistics Command resets the Motor Starts Count parameter to 0.

Description

The LTMR controller tracks the number of motor starts during the past hour and records this figure in the Motor Starts Per Hour Count parameter.

The LTMR controller sums start in 5 minutes intervals with an accuracy of 1 interval (+ 0/– 5 minutes), which means that the parameter will contain the total number of starts within either the previous 60 minutes or the previous 55 minutes.

This function is used as a maintenance function to avoid thermal strain on the motor.

Characteristics

The motor starts per hour function has the following characteristics:

Description

The Load Sheddings Count parameter contains the number of times the load sheddings protection function has been activated since the last Clear Statistics Command.

For information on the Load Sheddings protection function, refer to Load Shedding.

Description

There are three types of counting statistics:

• Auto restart immediate count

• Auto restart delayed count

• Auto restart manual count

For information on the Auto restart protection function, refer to Automatic Restart.

Description

The LTMR controller measures the maximum current level reached during the last start of the motor and reports the value in the Motor Last Start Current Ratio parameter for analysis of the system for maintenance purposes.

This value may also be used to help configure the long start threshold setting in the long start protection function.

The value is not stored in the non-volatile memory: it is lost at a power cycle.

Characteristics

The motor last start current ratio function has the following characteristics:

Description

The LTMR controller tracks the duration of the last motor start and reports the value in the Motor Last Start Duration parameter for analysis of the system for maintenance purposes.

This value may also be useful in setting the long start delay timeout used in the long start and definite trip overload protection functions.

The value is not stored in the non-volatile memory: it is lost at a power cycle.

Characteristics

The motor last start duration function has the following characteristics:

Description

The LTMR controller tracks motor operating time and records the value in the Operating Time parameter. Use this information to help schedule motor maintenance, such as lubrication, inspection, and replacement.

Description

The LTMR controller tracks the motor state and reports the following states by setting the corresponding boolean parameters:

Description

The LTMR controller tracks the time remaining to restart the motor according to one of the following events:

• Automatic reset

• Thermal overload

• Rapid cycle lockout

• Load shedding

• Automatic restart

• Transition time

If more than one timer is active, the parameter displays the maximum timer, which is the minimum wait for the trip response or the control function to reset.

Characteristics

The Minimum Wait Time function has the following characteristics: