Variable Frequency Drive · Quick Start Guide
INVT GD28 – Initial Commissioning
Compact general-purpose variable frequency drive with STO (SIL3), built-in brake chopper, and optional Ethernet communication card (PROFINET / EtherCAT / EtherNet/IP / Modbus TCP). This guide covers the essential commissioning steps.
0.2 kW – 22 kW
STO SIL3 (built-in)
SVC · V/F · AM · SM
Modbus RTU (RS-485)
Ethernet optional (EC-TX149)
Safety Notice Before Commissioning
Disconnect all phases of the supply voltage before wiring and secure against re-energisation. Do not remove the cover until at least 5 minutes after switching off the supply — dangerous capacitor voltage! The STO terminals (STO1, STO2) are factory-bridged to +24 V (STO inactive). For safety-related applications the jumpers must be removed and STO wired correctly in accordance with IEC 62061 / EN ISO 13849. The complete manual (GD28 Series VFD User Manual V1.3) must be read before commissioning.
Part A – Enter Motor Nameplate Data (Group P02)
First enter the rated values from the motor nameplate. These values are the basis for the subsequent autotuning (Part B), which automatically determines the electrical motor parameters (resistances, inductances).
| Parameter | Name | Value to Set | Description |
|---|---|---|---|
| P02.00 | Motor type | 0 | 0 = Asynchronous motor (AM) · 1 = Permanent magnet synchronous motor (SM) |
| P02.01 | Rated power | Nameplate (kW) | e.g. 2.2 kW |
| P02.02 | Rated frequency | 50.00 Hz | Standard for Europe; verify on nameplate |
| P02.03 | Rated speed | Nameplate (RPM) | e.g. 1450 RPM (4-pole, 50 Hz) |
| P02.04 | Rated voltage | Nameplate (V) | e.g. 400 V (delta connection) |
| P02.05 | Rated current | Nameplate (A) | Rated current for the selected wiring configuration |
Part B – Perform Autotuning (P00.15)
Autotuning automatically determines the electrical motor parameters and is the prerequisite for precise control. For vector control (P00.00 = 0 or 1) autotuning is mandatory; in V/F mode (P00.00 = 2, factory default) it is optional but recommended.
| Parameter | Value | Method | Disconnect load? |
|---|---|---|---|
| P00.15 | 1 | Complete rotary — highest accuracy, motor rotates. Best choice for demanding vector control. | Yes — motor must be unloaded (no-load) |
| 2 | Complete static — motor does not rotate, all static parameters determined. | No — load may remain coupled | |
| 3 | Partial static — partial parameters only, fastest tuning. | No — load may remain coupled |
Procedure on the operator panel
- Set P00.01 = 0 (control via keypad — prerequisite for autotuning).
- Set P00.15 to 1, 2 or 3 (see table) and confirm with
ENT. The display shows-TUN-. - Press the RUN key. The drive starts autotuning and shows the steps (e.g.
TUN-1). With rotary autotuning (P00.15 = 1) the motor now rotates. - Wait until the display shows
-End-. Autotuning is complete; the determined values are stored in P02.06–P02.14.
Safety during rotary autotuning (P00.15 = 1): The motor starts rotating on its own. Ensure the shaft turns freely, no persons are at risk, and the load is disconnected. If the motor cannot be disconnected, use static autotuning (P00.15 = 2 or 3).
P00.01 – Command Source
0
Keypad (Operator Panel) — Factory default
RUN/STOP keys on the 5-digit LED display control the drive directly.
RUN/STOP keys on the 5-digit LED display control the drive directly.
1
Terminal Control
Start/Stop via digital input terminals (DI1–DI4). Configure terminal functions in Step 5.
Start/Stop via digital input terminals (DI1–DI4). Configure terminal functions in Step 5.
2
Communication
Start/Stop via Modbus RTU (RS-485) or optional Ethernet card. Configure communication parameters in Step 6.
Start/Stop via Modbus RTU (RS-485) or optional Ethernet card. Configure communication parameters in Step 6.
| Parameter | Name | Value to Set | Description |
|---|---|---|---|
| P00.01 | Command source | 0 / 1 / 2 | Select according to the desired control method |
Communication mode note: When
P00.01 = 2, also check P00.02. Leave at default 0 for Modbus RTU. For the optional Ethernet card (EC-TX149), select the protocol under P24.00.
P00.06 – Main Frequency Source A
0
Digital Preset (Keypad) — Factory default
Frequency setpoint via operator panel or parameter
Frequency setpoint via operator panel or parameter
P00.10 (keypad frequency preset, default 50.00 Hz).
1
AI1 — Analogue Input 1
0–10 V or 0–20 mA (switchable via hardware jumper on the control board).
0–10 V or 0–20 mA (switchable via hardware jumper on the control board).
2
AI2 — Analogue Input 2
−10–10 V or 0–20 mA. Also suitable for bipolar setpoint inputs.
−10–10 V or 0–20 mA. Also suitable for bipolar setpoint inputs.
5
HDI1 — High-Speed Pulse Input
Pulse frequency up to 50 kHz.
Pulse frequency up to 50 kHz.
P05.00 = 0 (HDI1 as pulse input) required.
8
Multi-Speed (Simple PLC)
Up to 16 preset speeds selectable via DI bits (Group P10, parameters P10.02–P10.32).
Up to 16 preset speeds selectable via DI bits (Group P10, parameters P10.02–P10.32).
9
PID Controller Output
Frequency setpoint calculated by internal PID controller (Group P09).
Frequency setpoint calculated by internal PID controller (Group P09).
10
Communication (Modbus / Ethernet)
Frequency setpoint via RS-485 (register 0x2001) or optional Ethernet card.
Frequency setpoint via RS-485 (register 0x2001) or optional Ethernet card.
| Parameter | Name | Value to Set | Description |
|---|---|---|---|
| P00.06 | Main frequency source A | 0–8 | Select according to the desired setpoint source |
| P00.03 | Maximum output frequency | 50.00 Hz | Upper frequency limit; adjust only if required |
| P00.10 | Keypad frequency preset | 50.00 Hz | Only relevant when P00.06 = 0 (keypad setpoint) |
P00.11 / P00.12 – Ramp Times
Ramp times define the duration for the drive to accelerate from 0 Hz to maximum output frequency (P00.03) or decelerate in reverse. Ramp times that are too short may trigger overcurrent or overvoltage trips.
| Parameter | Name | Factory Default | Description |
|---|---|---|---|
| P00.11 | Acceleration time 1 | model-dep. | Time from 0 Hz to P00.03 (maximum output frequency) |
| P00.12 | Deceleration time 1 | model-dep. | Time from P00.03 to 0 Hz |
| P01.05 | Ramp curve type | 0 | 0 = Linear ramp · 1 = S-curve (smoother start for sensitive loads) |
Tip: For high-inertia loads (fans, pumps) 30–60 s is usually sufficient. With the brake chopper active (Step 7), shorter deceleration times are possible without risk of overvoltage trips.
Group P05 – Input Terminals (DI1–DI4, HDI1)
The GD28 has 4 physical digital inputs (DI1–DI4) and the high-speed input HDI1 (up to 50 kHz). All DI terminals support PNP and NPN wiring (switchable via hardware jumper on the control board).
| Terminal | Parameter | Factory Default | Common Alternatives |
|---|---|---|---|
| DI1 | P05.01 | 1 = Forward run | 2 = Reverse run · 56 = Emergency stop |
| DI2 | P05.02 | 4 = JOG forward | 2 = Reverse run · 9 = External fault |
| DI3 | P05.03 | 7 = Fault reset | 8 = Pause · 13–15 = Frequency source A/B/combo |
| DI4 | P05.04 | 0 = No function | Can also be used as PTC input (motor temperature sensor) |
| HDI1 | P05.00 | 0 = Pulse input (up to 50 kHz) | 1 = Normal digital input; function via P05.11 |
STO Terminals (Safe Torque Off) – SIL3 / IEC 61800-5-2
| Terminal | Function | Note |
|---|---|---|
| STO1 | STO channel 1 (+24V–STO1) | Factory-bridged to +24 V (STO inactive). For SIL3 applications, remove jumper and connect external safety signal. |
| STO2 | STO channel 2 (+24V–STO2) | Redundant second channel. Both channels must be active simultaneously. Response time ≤ 20 ms. Use shielded cable ≤ 25 m. |
STO Fault Codes: E40 = STO triggered (normal, resettable) · E41 = STO channel 1 exception · E42 = STO channel 2 exception (device restart required in both cases).
Virtual DI terminals: DI5–DI8 (
P05.05–P05.08) are virtual inputs with no physical terminal — switchable via communication only (Modbus register 0x200A).
Group P14 – Serial Communication (RS-485)
| Parameter | Name | Recommended Setting | Description |
|---|---|---|---|
| P14.00 | Device address | 1 | Unique slave address 1–247. Factory default: 1. 0 = Broadcast (receive only). |
| P14.01 | Baud rate | 4 | 4 = 19200 baud (factory default) · 3 = 9600 · 5 = 38400 · 6 = 57600 · 7 = 115200 |
| P14.02 | Data format | 0 | 0 = N,8,1 RTU (recommended for most PLCs) · 1 = E,8,1 RTU (factory default) · 2 = O,8,1 RTU |
| P14.04 | Communication timeout | 0.0 s | 0.0 = disabled. In production machines, 1.0–5.0 s is recommended. |
| P14.05 | Behaviour on comm. fault | 0 | 0 = Alarm + coast stop · 2 = Stop (communication mode only) |
Key Holding Registers (FC 03 read / FC 06 write)
| Description | Hex Address | Dec. | Value (Hex) | Value (Dec) | Meaning |
|---|---|---|---|---|---|
| Control word (write) | 0x2000 | 8192 | 0x0001 | 1 | Forward run (Bit 0 = 1) |
| 0x2000 | 8192 | 0x0020 | 32 | Deceleration stop (Bit 5 = 1) | |
| 0x2000 | 8192 | 0x0040 | 64 | Fault reset (Bit 6 = 1) | |
| Frequency setpoint (write) | 0x2001 | 8193 | 0x1388 | 5000 | 50.00 Hz · Resolution 0.01 Hz · 5000 = 50.00 Hz |
| Output frequency (read) | 0x3000 | 12288 | Actual value | Actual output frequency (0.01 Hz) | |
| Output current (read) | 0x3004 | 12292 | Actual value | Output current (0.01 A) | |
Control word bit overview (0x2000):
Bit 0 = Forward run · Bit 1 = Reverse run · Bit 2 = JOG forward · Bit 3 = JOG reverse · Bit 4 = Coast stop · Bit 5 = Deceleration stop · Bit 6 = Fault reset · Bit 7 = Pause.
For full communication control: set
P00.01 = 2 (command source: communication) and P00.06 = 10 (frequency source: communication).
USB-C parameterisation without mains power: The GD28 features a Type-C debug interface for the INVT Workshop software — parameters can be read and written without mains voltage applied. Ideal for pre-parameterisation at the office or in the warehouse.
P08.39 / P08.40 – Dynamic Braking (built-in, all power ratings)
The GD28 has a built-in brake chopper across all power ratings. To use it, a suitably rated external braking resistor must be connected to the braking resistor terminals on the drive (see wiring diagram in manual V1.3).
| Parameter | Name | Value to Set | Description |
|---|---|---|---|
| P08.39 | Enable dynamic braking | 1 | 0 = Disabled (factory default) · 1 = Enabled |
| P08.40 | Braking threshold voltage | 700 V | DC bus voltage at which the brake chopper engages. Factory default for 380 V models: 700 V · For 220 V models: 380 V. Range: 200.0–2000.0 V. |
Braking resistor sizing: Calculate the resistance value and duty cycle according to the manual (V1.3). Matching INVT braking resistors for the GD28 are available in the spstiger shop. Do not operate an undersized resistor continuously — risk of overheating.
Complete all items before the first start
Fault codes: Faults are displayed as Exx (e.g. E4 = Overcurrent during acceleration · E10 = DC bus undervoltage · E40 = STO triggered). Fault history in P07.27–P07.32. Full fault list in manual (V1.3, Troubleshooting chapter).
Frequenzumrichter INVT GD28 mit STO und optionaler Kommunikationskarte
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