MITSUBISHI ELECTRIC FR-D700 Inverter Complete Guide

MITSUBISHI ELECTRIC FR-D700 Inverter Complete Guide

Introduction: A compact body contains powerful strength

The Mitsubishi Electric FR-D700 series is a compact universal frequency converter designed for the global market, with a power range of 0.1kW to 15kW, supporting single-phase 100V/200V and three-phase 200V/400V power inputs. It inherits the compact size of the FR-S500 series, but achieves a qualitative leap in performance, functionality, and reliability. This series is equipped with a built-in safety stop function (compliant with the EU Machinery Directive), a long-life design (key components have a lifespan of up to 10 years), and universal magnetic flux vector control, which can output 150% starting torque at 1Hz. Whether it is conveyor belts, fans, water pumps, winding machines, textile machinery, or small lifting equipment, FR-D700 can provide efficient and stable driving solutions.

For engineers facing the replacement of old frequency converters (such as FR-S500 or other branded products) or the need for new equipment matching, mastering the selection points, parameter settings, peripheral circuit design, and troubleshooting methods of FR-D700 can significantly shorten the debugging cycle, reduce maintenance costs, and improve equipment reliability. This article provides a comprehensive technical guide based on the product technical specifications and combined with on-site engineering experience.

Security feature: Integrated STO, simplifies compliance design

One of the biggest highlights of the FR-D700 series is the built-in Safe Torque Off (STO) function. Previously, in order to make the frequency converter comply with the EU Machinery Directive (2006/42/EC), it was usually necessary to add safety relays or contactors externally. Nowadays, FR-D700 receives emergency stop signals through two independent hardware channels (terminals X1 and X2). When the signal is disconnected, the frequency converter immediately cuts off the output stage drive, achieving torque free sliding stop of the motor. This feature complies with the following safety standards:

EN 61800-5-2 (Safety Requirements for Adjustable Speed Electric Drive Systems)

IEC 61508 (SIL 2 or SIL 3 level)

ISO 13849-1（PL d / Cat. 3）

Wiring and application points:

The safety stop terminals (X1, X2) require 24V DC by default to operate. Both channels must be powered simultaneously, otherwise triggering a stop.

Common error on site: Only one channel was connected, causing the frequency converter to fail to start. When troubleshooting, a multimeter can be used to measure the voltage between X1-SD and X2-SD, which should be 24V.

The safety stop function cannot replace mechanical brakes. For loads that need to maintain their position (such as elevators), brake contactors or electromagnetic brakes still need to be configured in the external circuit.

Troubleshooting: When the frequency converter displays an "SA" or "S-R" alarm (safety stop activated), first check if the external emergency stop button is pressed, and then check if the safety relay output is normal. If the external signal is normal but the frequency converter is still in a safe state, it may be an internal safety circuit fault and the manufacturer needs to be contacted for maintenance.

Long life design: worry free operation for 10 years

FR-D700 is the first frequency converter to propose a 10-year design life in popular products (based on JEMA guidelines, traditional products have a fan life of only 2-3 years and a capacitor life of 5 years). Specific implementation measures:

Cooling fan: High quality bearing fan with a design lifespan of 10 years. Models of 1.5kW and above are equipped with a top detachable fan as standard, which can be replaced without removing the main circuit wiring, greatly facilitating on-site maintenance.

Main circuit smoothing capacitor: Select a capacitor that can withstand an ambient temperature of 105 ℃ and withstand a high temperature load for about 5000 hours. Under the condition of an annual average of 40 ℃ and an output current of 80% of the rated current, the calculated lifespan is 10 years.

Control circuit capacitor: also using long-life specifications.

Built in lifespan diagnostic function: It can monitor the degradation level of the main circuit capacitor, control circuit capacitor, surge current limiting circuit, and cooling fan, and notify the replacement requirement in advance through alarm output (such as parameters Pr.255~Pr.258). The capacitance can be automatically measured by setting parameters while in a stopped state and then powering on again.

Engineering suggestion:

Regularly (every 6 months) view the lifespan diagnostic values (Pr.255~Pr.259) through the panel or software. When any value is below 10%, plan to replace the corresponding component.

Although the fan is designed to have a lifespan of 10 years, it is recommended to check its flexibility and abnormal noise every 3-4 years in environments with severe dust or high temperatures.

Before powering on the frequency converter after long-term storage (more than 2 years), voltage should be slowly applied through a voltage regulator to "activate" the capacitor, to avoid direct full voltage input causing capacitor failure.

Excellent motor control performance

4.1 General Magnetic Flux Vector Control

FR-D700 adopts universal flux vector control, which significantly improves low-speed torque compared to traditional V/f control. Specific indicators:

150% torque @ 1Hz (3.7kW and below)

200% torque @ 3Hz (3.7kW and below)

Built in self-tuning function, which can automatically measure parameters such as the primary resistance (R1) of the motor, optimizing the control effect. Self tuning can be completed without the motor rotating (only static self-tuning), which is very friendly to motors already installed on the equipment.

Applicable scenarios: loads that require high starting torque, such as conveyor belts, elevators, washing machines, mixers, etc. For square torque loads such as fans and pumps, energy saving can be achieved through optimal excitation control.

4.2 Optimal excitation control

By automatically adjusting the excitation current, the motor efficiency is maintained at its optimal state, especially suitable for equipment (fans, pumps) where load torque varies with speed. Tested to save about 10-20% of electrical energy under light load.

4.3 Regeneration Avoidance Function

When the motor is dragged beyond the set frequency due to external loads (such as another fan), the frequency converter will automatically increase the output frequency to suppress regenerative energy and reduce the occurrence of overvoltage tripping (E.OV). Very suitable for parallel fan, compressor and other systems.

4.4 Other Practical Functions

Traverse control: used in spinning, drawing and other winding processes to prevent uneven accumulation of yarn or metal wires by periodically changing the frequency. Parameters Pr.592~Pr.597 can be set for swing amplitude, swing period, etc.

PID control: Equipped with a built-in PID regulator, it can be used for constant pressure water supply, constant temperature control, etc., without the need for an external controller.

Power outage deceleration stop function: When the power is cut off or under voltage, the automatic deceleration stops the motor smoothly, avoiding free sliding. It is suitable for situations such as machine tool spindles that require controllable parking.

Dancer control: Constant tension control is achieved by connecting the position signal of the dance roller through analog input.

Selection and Rating Interpretation

5.1 Model Code Description

FR-D720- □ K (three-phase 200V), FR-D740- □ K (three-phase 400V), FR-D720S - □ K (single-phase 200V), FR-D710W - □ K (single-phase 100V). The number inside indicates the applicable motor power (kW). For example, FR-D720-2.2K corresponds to a 2.2kW three-phase 200V frequency converter.

Differences in export specifications: Japanese specifications, North American specifications (NA), European specifications (EC), and Chinese specifications (CHT) differ in terms of main circuit terminal names, initial control logic settings (drain/source), and initial parameter values (such as fundamental frequency 60Hz vs 50Hz). When selecting, it is important to confirm the certification requirements of the target market (UL, CE, KC, EAC, etc.).

5.2 Current and Overload Capacity

Taking FR-D720-2.2K as an example:

Rated output current: 10.0A (corresponding to 2.2kW)

Overload capacity: 150% 60 seconds, 200% 0.5 seconds (inverse time characteristic)

Applicable motor: Standard Mitsubishi 4-pole motor

Selection trap: If the rated current of the motor is greater than the rated output current of the frequency converter, even if the power is matched, it may not be able to operate at full load for a long time. For heavy-duty applications such as reciprocating compressors and frequent start stop, a higher capacity should be selected and a longer acceleration and deceleration time should be set.

5.3 Braking Capacity

Built in braking transistor (0.4K and above), can be directly connected to external braking resistors (MMS/MYS type or high load FR-ABR). Braking torque:

0.1K~0.2K: 150% (without built-in brake transistor, no resistor can be added)

0.4K：150%

0.75K：100%

1.5K~2.2K：50%

3.7K and above: 20% (braking only based on motor loss)

Important: When using a braking resistor, Pr.70 (special regenerative braking duty cycle) and Pr.30 (regenerative function selection) must be set correctly, otherwise the resistor may overheat and be damaged. For frequent braking or high inertia loads, it is recommended to use FR-BU2 braking units or FR-CV regenerative rectifiers.

Communication and Programming: Flexible Integration Capability

6.1 Built in RS-485 communication

FR-D700 comes standard with an RJ45 interface (PU interface) and supports:

Mitsubishi inverter protocol (computer link communication): up to 32 stations can be set, with a maximum communication speed of 38400bps. Added 'multi command mode', reducing data processing time to 1/4 of the original.

Modbus RTU protocol: can be directly connected to common SCADA or PLC (such as Mitsubishi FX series). Register addresses are mapped to Modbus standards, making configuration simple.

Wiring and configuration:

Using shielded twisted pair cables, the terminal resistance should be set at both ends (SW2 switch).

Communication parameters: Pr.117~Pr.124 (station number, speed, data bit, stop bit, parity check, etc.).

If the operation and frequency are remotely controlled through RS-485, do I need to set Pr.79=1 (external operation mode) or Pr.79=2 (PU operation mode)? In fact, remote communication usually sets Pr.79 to 0 or 1, and cooperates with Pr.338~Pr.339, etc. Clearer: Set Pr.79 to 0 (combination mode) and select the communication operation command (Pr.338=1) and communication frequency command (Pr.339=1).

Troubleshooting: Communication timeout (E.PUE). Check the polarity of the wiring (+corresponds to SDA, - corresponds to SDB), confirm that the station number is consistent, and the communication speed matches. Quickly locate using the "Communication Test" function of FR Configurator software.

6.2 PC Software FR Configurator

By connecting the PC and frequency converter through RS-485, the FR Configurator (SW3-SETUP-WE) provides guided parameter setting, monitoring, graphical data (waveform display), and program conversion functions - it can easily convert the parameter files of the old FR-S500 series to FR-D700 format with just one click, greatly simplifying the upgrade and replacement work.

Practical tip: Use the "Batch Copy" function to save the parameters of a debugged frequency converter to a PC, and then write them to other frequency converters in the same batch to ensure consistency. It is also possible to store up to 3 sets of parameters and copy them offline through parameter unit FR-PU07 (supporting 8 languages).

Key points for selecting and installing peripheral devices

7.1 Circuit breakers and contactors

Input side circuit breaker: Select according to the input current of the frequency converter, refer to the rated table (such as FR-D720-2.2K using 15A MCCB). For the North American market, Class T fuses or UL489 circuit breakers are required.

Input side contactor: used for emergency power cut-off or maintenance isolation, but prohibits frequent start stop (switch life is about 1 million times). If frequent start stop is required, control terminals STF/STR should be used.

Output side contactor: Switching is only allowed when both the frequency converter and motor are stopped (such as power frequency standby switching). Cutting off the output during operation will cause overcurrent tripping.

7.2 Reactors and Filters

AC Reactor FR-HAL: It is recommended to install when the capacity of the power transformer is greater than 500kVA or when harmonic suppression is required. For single-phase 100V input and transformer ≥ 50kVA, an AC reactor must be installed to prevent surge overvoltage.

DC Reactor FR-HEL: Connect between P1 and P/+terminals (short-circuit wire needs to be removed). Used for power factor improvement and harmonic suppression.

EMC filter: In order to comply with EN61800-3 C3 category (second environment), SF series filters can be selected. The FR-D700-042 model has a built-in C2 level filter (restricted distribution in the first environment), with a maximum motor cable length of 10m.

Noise filter FR-BIF (H): for radio interference, installed on the input side.

Line noise filter FR-BSF01: used to reduce sensor misoperation, can be installed on the output cable.

7.3 Selection of Braking Resistors

Taking FR-D720-2.2K (R2 chassis) as an example: the minimum allowable resistance value Rmin is 19.5 Ω, the maximum resistance value Rmax is 47.1 Ω, the continuous braking power PBRcont is 2.2kW, and the maximum braking power PBRmax is 3.3kW (1 minute/10 minutes). When selecting MRS or MYS type resistors, their resistance value must fall between Rmin and Rmax, and the power must not be less than the actual braking energy. If a high load braking resistor FR-ABR is used, the duty cycle can be increased to 10% ED.

Calculation example: The load has a large inertia and needs to brake for 5 seconds every 20 seconds. The average braking power is equal to the actual peak power multiplied by (5/20). Ensure that the average value is less than PBRcont and the peak value is less than PBRmax.

Fault prompt: When the resistor is overheated or damaged, the frequency converter may report "E.OV" (regenerative overvoltage) or "E.bE" (abnormal brake transistor). The latter requires immediate power outage and replacement of the frequency converter.

7.4 Wiring precautions

The control circuit terminals use spring clip terminals, which do not require a screwdriver to tighten and are reliably crimped. However, when disassembling, a small flat head screwdriver is needed to press down on the release hole.

The main circuit terminal is a screw terminal, and it is recommended to use a flexible wire with insulated terminals, with a torque of the specified value (about 0.8~1.2N · m).

The output terminals U/V/W of the frequency converter must not be connected to the power supply, otherwise it will be immediately damaged.

The signal cable and power cable should be separated by at least 10cm, and the shielding layer should be grounded at one end (terminal 5). Do not form a loop by grounding the outer shell.

When the length of the motor cable is too long (exceeding 50m), leakage current caused by distributed capacitance may cause thermal relay misoperation. It is recommended to use Pr.9 electronic thermal relay instead of external thermal relay or reduce the carrier frequency (Pr.72).

Debugging and rapid parameter setting

8.1 Basic parameter initialization

For first-time use, perform parameter initialization (set Pr.77=1, then clear the parameters to factory values through the panel). Then modify as needed:

Pr.1 upper limit frequency (maximum 0~120Hz, extended mode up to 400Hz)

Pr.2 lower limit frequency (usually 0Hz)

Pr.3 Fundamental frequency (set as the rated frequency of the motor, such as 50Hz)

Pr.7 acceleration time, Pr.8 deceleration time (unit: 0.1s, range: 0~3600s)

Pr.9 electronic thermal relay current (set as motor rated current)

Pr.79 operating mode (0=combination mode, 1=external terminal, 2=PU panel, 3=external+PU combination, etc.)

8.2 One click quick debugging

Rotate the SET knob to directly modify the frequency, and use the "MODE" button on the panel to switch monitoring modes (frequency, current, voltage, etc.). For applications that require vector control, first perform self-tuning (Pr.96=1,3 or 4), then set Pr.80=motor capacity, Pr.81=motor pole number, Pr.83=motor rated voltage, etc.

8.3 Password Protection

Setting Pr.296 and Pr.297 can lock parameters to prevent accidental modifications. 4-digit password, only by entering the correct password can parameters be modified after locking. Suitable for applications that require protection of proprietary settings.

Common fault codes and solutions

Fault code description, common causes, and solutions

E. During OC1 acceleration, the overcurrent acceleration time is too short, the motor winding is short circuited, and the mechanical jamming prolongs the acceleration time; Check the insulation resistance of the motor; Disconnect load test

E. Sudden changes in OC2 constant speed overcurrent load and increased load stability due to contactor action on the output side of the frequency converter; Prohibit switching output contactors during operation

E. OC3 deceleration overcurrent deceleration time is too short, improper configuration of braking resistor prolongs deceleration time; Check the resistance of the braking resistor

E. OV1/2/3 overvoltage deceleration time is too short, regeneration energy is too large, and the power supply voltage is too high, which prolongs the deceleration time; Install braking resistor; Check input voltage

E. THM motor overload motor long-term overload, cooling fan fault check load current; Set the correct Pr.9

E. THT frequency converter overload, insufficient frequency converter capacity, poor heat dissipation, and increased frequency converter capacity; Clean the radiator; Reduce the carrier frequency

E. FIN radiator overheating, high ambient temperature, fan damage, dust accumulation. Check the ambient temperature; Replace the fan; Clean the air duct

E. IPF instantaneous power outage, power interruption, enable automatic restart function (Pr.57) or do not handle

E. Use a megohmmeter to check the insulation of the ground fault motor or cable on the GF output side for short circuit to ground; Eliminate grounding faults

E. Check if the U/V/W terminals of the LF output phase loss motor are loose due to wire breakage and poor contact of the contactor; Measure the resistance of the motor coil

E. PUE PU communication error RS-485 wiring error, station number conflict check wiring; Confirm that the station number is unique; Reduce communication speed

During SA safety stop, the STO terminal is not powered on or the emergency stop button is pressed to restore power supply to the safety circuit; Check the emergency stop switch

No display, the frequency converter is not powered on, the power supply is not input, and the internal switch power supply is damaged. Measure the R/S/T voltage; Check the fuse; send for repair

Fault reset: After troubleshooting, it can be reset through the STOP/RESET button or external RES terminal. Before resetting faults such as overcurrent and overvoltage, it is necessary to ensure that the fault source has been eliminated.

Upgrade and replace: from FR-S500 to FR-D700

A large number of current FR-S500 series have been discontinued, and FR-D700 is the best alternative model. Attention when replacing:

Mechanical dimensions: The installation holes of FR-D700 are exactly the same as those of FR-S500 (0.75K and below), and can be directly replaced. The appearance of 1.5K and above has slightly changed, but it is still compatible with the original opening (see the external drawing for specific dimensions).

Main circuit wiring: The terminal names are basically the same (R, S, T; U, V, W), but the terminal numbers of the control circuit have changed and need to be re crimped according to the terminal definition table.

Parameter Conversion: Use the "Conversion" function of the FR Configurator software to import the original S500 parameter file (. prm) and automatically generate the parameter values corresponding to D700. After conversion, it is still recommended to manually review, especially Pr.3 (fundamental frequency), Pr.7/Pr.8 (acceleration and deceleration time), Pr.9 (electronic thermal relay), Pr.72 (carrier frequency), etc.

Functional differences: D700 has added functions such as safety stop, lifespan diagnosis, optimal excitation control, and swing frequency; At the same time, some less frequently used functions have been cancelled (such as a maximum of 15 segments for multi-stage speed). If the original S500 used these functions, alternative solutions need to be found in D700.

Peripheral devices: The original braking resistors, reactors, filters, etc. can continue to be used, but it is necessary to confirm whether the resistance and power meet the minimum/maximum resistance range allowed by D700.

Alternative steps:

Power off, disconnect, and record the original wiring markings.

Remove the old frequency converter and install D700.

Connect according to the new terminal definition (especially pay attention to the difference between the control circuit common terminal SD and PC - drain type logic SD is connected to the common terminal, and source type logic PC is connected to the common terminal).

Import converted parameters through FR Configurator or manually input them.

No load test (disconnect the motor), check whether the running direction and frequency command are normal.

Load test run, monitor current and vibration.

Harmonic suppression and environmental compliance

11.1 Japanese Harmonic Suppression Guidelines (applicable to the Japanese market)

Most specifications of FR-D700 belong to the input current category of 20A or less, excluding specific users, and must comply with the JEM-TR226 guidelines. Determine whether it is necessary to install a reactor:

Single phase 100V input: 0.75kW and below → It is recommended to connect AC or DC reactors

Single phase 200V input: 2.2kW and below → It is recommended to connect AC or DC reactors

Three phase 200V input: 3.7kW and below → It is recommended to connect AC or DC reactors

For higher power, harmonic currents need to be calculated according to the "High Voltage Receiving Users" guide, and AC+DC reactors or high power factor converters (FR-HC2) may need to be installed.

11.2 Leakage Current and Leakage Protection

The PWM waveform on the output side of the frequency converter may generate leakage current between ground and line, which may cause the 30mA residual current circuit breaker to trip incorrectly. Solution:

The rated sensitivity current of the residual current circuit breaker (Mitsubishi NV series) for harmonic/surge suppression should be ≥ 10 times (total leakage current of the line).

Lowering the carrier frequency (Pr.72) can reduce leakage current.

Install an output side noise filter (FR-BSF01) or apply a magnetic ring to the motor cable.

11.3 RoHS and Environmental Protection

FR-D700 complies with the EU RoHS Directive (2011/65/EU) and has the<3>mark printed on its packaging, indicating that it does not contain harmful substances such as lead, mercury, cadmium, hexavalent chromium, PBB, PBDE, etc.