Commissioning Mitsubishi Electric FR-D700 and FR-E700 Variable Frequency Drives
Mitsubishi Electric FR-D700 and FR-E700 variable frequency drives are industrial standards due to their hardware durability, but they require accurate parameter settings during basic commissioning. Our engineers at the Kyiv warehouse support customers with terminal wiring and parameter programming daily, which is why we compiled this practical manual. Starting the motor via the VFD keypad (PU mode) and switching to control terminals (External mode) often causes confusion due to specific mode-selection logic. Without a clear understanding of control terminal signals and Pr. 79 parameters, you risk locking the drive or getting start faults. The wiring schemes below have been verified on our service center test benches.
Power Terminals and Main Circuit Connection
For standard three-phase motor connections, connect the power supply lines to terminals R/L1, S/L2, T/L3, and connect the motor cables to terminals U, V, W. If you are using a single-phase input VFD model (such as the FR-D720-042-EC), the 220V power supply must be connected to terminals R/L1 and S/L2, leaving terminal T/L3 unconnected.
Strictly follow grounding instructions: connect both the VFD chassis and the motor frame to the PE terminal. We recommend using shielded motor cables to minimize electromagnetic interference, and the total cable length should not exceed 50 meters without installing an output motor reactor.
Connecting a single-phase fan or pump motor to a standard three-phase output VFD is a frequent custom task. From our experience, running single-phase motors with their original starting capacitors is unstable and leads to rapid motor overheating. The most effective technical solution is to remove the capacitor from the motor circuitry completely. This isolates the two internal windings: the main (run) winding and the auxiliary (start) winding.
Wire these windings according to this scheme:
- Main winding connects directly to the U and V output terminals of the VFD.
- Auxiliary winding connects to the U and W output terminals. Terminal U serves as the common connection point for both windings.
Once wired, the VFD will instantly trip on E.ILF (Output Phase Loss Fault) due to current asymmetry. To bypass this hardware protection, change the default setting: set parameter Pr. 251 = 0 (Disable output phase loss). This engineering trick enables safe speed control for single-phase motors, though the torque at low frequencies will be lower compared to three-phase motors.
Terminal Control and Parameter Pr. 79: Preventing the External Lock Trap
The active control source of a Mitsubishi VFD is determined by parameter Pr. 79. Set Pr. 79 = 2 to enable drive operation via physical STF/STR terminals and frequency setting via the analog input.
By default, the drive is set to Pr. 79 = 0 (external control is prioritized, but switching via keypad is allowed). Setting Pr. 79 = 2 (Terminal Operation Mode) disables the PU keypad RUN button entirely. This represents a classic external command trap for junior technicians, where pressing RUN on the keypad does nothing.
With Pr. 79 = 2, control signals operate as follows:
- To run Forward, close a contact between control terminal STF and common terminal SD (NPN sink logic) or terminal PC (PNP source logic).
- To run Reverse, close a contact between terminal STR and common terminal SD or PC.
- Frequency is controlled by applying a 0-10V voltage signal to analog terminal 2 (with terminal 5 as common) or a 4-20mA current signal to terminal 4 (with terminal 5 as common).
Verify the physical SINK/SOURCE slide switch on the control board. For European models (with the -EC suffix), it defaults to SOURCE (PNP) logic, meaning the common line is terminal PC (+24V). For Japanese and Asian models, it is often set to SINK (NPN) logic, where the common line is terminal SD (0V). Check the switch position before wiring external jumpers.
Configuring Digital Inputs: Parameters Pr. 180 to Pr. 186
The function of each digital input terminal on FR-D700 and FR-E700 VFDs can be reconfigured using parameters Pr. 180 to Pr. 186. To configure multi-speed operations, assign function codes 0, 1, and 2 for low, middle, and high speeds respectively.
Default digital input configurations are listed below:
| Parameter | Default Terminal | Factory Assigned Function | Default Function Code |
|---|---|---|---|
| Pr. 180 | STF | Forward rotation start | 0 |
| Pr. 181 | STR | Reverse rotation start | 1 |
| Pr. 182 | RL | Low-speed operation | 2 |
| Pr. 183 | RM | Middle-speed operation | 3 |
| Pr. 184 | RH | High-speed operation | 4 |
| Pr. 185 | MRS (for D700) / RT (for E700) | Output stop / Second function selection | 5 |
| Pr. 186 | RES (for D700) / AU (for E700) | Reset / Current input selection | 6 |
To run the VFD at three preset speeds, combine digital input signals on terminals RL, RM, and RH. Preset speed values are configured in separate registers: Pr. 4 (high speed, default 50Hz), Pr. 5 (middle speed, default 30Hz), and Pr. 6 (low speed, default 10Hz). Activating the corresponding digital terminal forces the drive to run at the preset frequency, eliminating the need for an external speed potentiometer.
Motor Configuration and Pr. 96 Auto-Tuning Procedure
To achieve maximum shaft torque and accurate sensorless vector control, perform the motor auto-tuning procedure using parameter Pr. 96. Run either a static auto-tune (without motor rotation, Pr. 96 = 1) or a dynamic auto-tune (with motor rotation, Pr. 96 = 21).
Before initiating the auto-tuning process, input the motor nameplate data into these registers:
- Pr. 80 — Rated motor capacity in kW (e.g., 1.5 or 2.2).
- Pr. 81 — Number of motor poles. Set to 4 for a 1500 rpm motor, 2 for a 3000 rpm motor, and 6 for a 1000 rpm motor.
- Pr. 9 — Rated motor current in Amps (this sets the thermal overload protection threshold).
- Pr. 83 — Rated motor voltage (typically 220V or 380V depending on star/delta wiring).
- Pr. 84 — Rated motor frequency (default 50Hz).
- Pr. 7 — Acceleration time. Configure according to your load application (typically 5 to 10 seconds for pump systems).
- Pr. 8 — Deceleration time. For high-inertia fan applications, we recommend increasing this to 15-20 seconds to prevent overvoltage trips (E.OV3 error).
- Pr. 1 — Maximum frequency (default 120Hz; we recommend limiting this to 50Hz or 60Hz to protect standard industrial motors).
- Pr. 2 — Minimum frequency (default 0Hz; for motors operating under load without external cooling, we recommend setting a minimum limit of 15-20Hz).
Follow these steps to execute the auto-tuning sequence:
- Switch the VFD to PU control mode by setting parameter Pr. 79 = 1.
- Set parameter Pr. 96 = 1 (if the motor is coupled to the load and the shaft cannot rotate) or Pr. 96 = 21 (recommended, shaft is uncoupled and free to rotate).
- Press the RUN key on the PU keypad.
- The display indicator will start flashing, indicating tuning is in progress. The process takes 10 to 30 seconds.
- Upon successful completion, the display shows 3. If the tuning fails (showing 8 or 9 on the screen), check the motor phase wiring and verify the motor nameplate parameter values.
Comparing FR-D700 and FR-E700 VFD Series
For simple applications like conveyors and ventilation fans, the FR-D700 series represents a highly cost-effective solution. For complex applications requiring high startup torque at low speeds (hoists, extruders), use the FR-E700 series, which features advanced hardware capabilities and high-tier vector control.
| Technical Feature / Function | FR-D700 Series | FR-E700 Series |
|---|---|---|
| Power Range | 0.1 kW to 7.5 kW | 0.1 kW to 15 kW |
| Control Method | V/f control, simple magnetic flux vector control | Advanced Magnetic Flux Vector Control (high-tier sensorless vector control) |
| Overload Capacity | 150% for 60 seconds | 200% for 3 seconds, 150% for 60 seconds |
| Analog Inputs | 1 (voltage or current selectable) | 2 (dedicated 0-10V voltage and 4-20mA current inputs) |
| Built-in RS-485 | Yes (RJ45 port for Modbus RTU) | Yes (supports CC-Link, Profibus communication option cards) |
| Safety Torque Off (STO) | Yes, integrated safety input | Available as a factory option on specific models |
We maintain both series in our Kyiv warehouse stock, ensuring immediate shipment for your industrial plant upgrade projects.
Frequently Asked Questions
How do I resolve the E.OC1 (Overcurrent during acceleration) fault?
The E.OC1 fault typically indicates that the acceleration rate is too fast for the load inertia. Increase the acceleration time in parameter Pr. 7 by 2 to 3 seconds. Also, verify that parameter Pr. 0 (torque boost) is not set too high, as excessive boost values saturate the motor magnetic circuit and cause high current spikes during startup.
How can I configure FR-D700 / FR-E700 VFDs for Modbus RTU communication?
To enable control via the integrated Modbus RTU RJ45 port, set parameter Pr. 79 = 0 or Pr. 79 = 6. You must also configure the communication parameters: Pr. 117 (station address), Pr. 118 (baud rate, default 9600 bps), Pr. 120 (data format), and set Pr. 549 = 1 to select Modbus RTU protocol instead of the native Mitsubishi protocol.
The VFD trips on E.THT. What does this mean and how do I adjust the protection?
An E.THT fault indicates that the electronic thermal overload relay has triggered to protect the motor from overheating. Ensure parameter Pr. 9 (rated motor current) is programmed to match the nominal Amps on the motor nameplate. If the motor operates at low speeds (below 20Hz) under high load, it lacks adequate cooling from its shaft-driven fan; install an external forced cooling fan if this is the case.
How do I connect an external speed reference potentiometer?
An external 1k to 5k Ohm analog potentiometer connects to three control terminals: terminal 10 (power +5V supply), terminal 2 (analog voltage input), and terminal 5 (common). After wiring, ensure parameter Pr. 79 is set to 2 to accept the external speed reference.
Can I use terminal RES as an emergency stop input?
No, terminal RES is designed exclusively to reset the VFD internal microprocessor after a fault has occurred. Activating the RES input while the motor is running immediately shuts off the output transistors, causing the motor to coast to a stop. For safe stopping, open the STF start circuit or utilize the dedicated Safety Torque Off (STO) terminal loops.
Conclusion and Expert Recommendations
Proper operation mode selection and precise parameter configuration allow users to fully utilize the potential of Mitsubishi FR-D700 and FR-E700 variable frequency drives. From our experience, most service requests result from incorrect Pr. 9 settings or analog wiring mistakes. If you require expert support in VFD selection or complex industrial automation layout, our engineers are always ready to assist. Explore the full range of drives in our catalog: you can purchase Mitsubishi Electric frequency inverters directly from our stock in Kyiv, and you can also check our Schneider Altivar setup guide or read our manual for Mitsubishi Electric equipment.
