Commission a VFD in a fixed order: factory reset → motor nameplate data → command and setpoint source → limits and ramps → control mode → motor identification run → save and back up. Nameplate data comes first because every later calculation — current limit, torque estimation, vector control model — is derived from it. On a SINAMICS G120 that means p0304 (voltage), p0305 (current), p0307 (power), p0310 (frequency) and p0311 (speed), entered inside the quick-commissioning wizard p0010 = 1. Skipping the reset or entering nameplate data after the control mode is the usual reason a drive behaves unpredictably.
- Always start from a known state. A used drive carries someone else's settings, and troubleshooting an unknown baseline wastes more time than the reset costs.
- Enter nameplate data exactly as printed, including the connection type (star or delta) that matches how the motor is actually wired.
- Vector control without a motor identification run performs worse than plain V/f. Run it or do not select vector.
- A parameter set that exists only inside the drive is not backed up. Export it, and store it with the machine documentation.
Why Parameter Order Matters
A VFD's parameters are not independent. Many are calculated or range-limited from others, so entering them in the wrong order produces values that look right on the display but are internally inconsistent.
The clearest example is motor data. When you enter rated current, the drive derives its default current limit, its overload protection thresholds and — in vector mode — the parameters of its internal motor model. Enter the current limit first and then change rated current, and the drive silently recalculates, overwriting what you set. Engineers who commission drives in a habitual order stop encountering this class of problem entirely.
Most manufacturers acknowledge this by providing a quick commissioning or basic commissioning mode that walks through the parameters in the correct sequence and blocks access to dependent values until the prerequisites are entered. On SINAMICS drives this is p0010 = 1; the wizard in Startdrive or the TIA Portal drive object does the same job graphically. Use it. Entering parameters ad hoc from a list is how experienced engineers create problems for themselves.
Step 0: Factory Reset Before Anything Else
Any drive that is not brand new should be reset to factory defaults before commissioning. A spare from the store may have been configured for a different machine years ago; a replacement pulled from another line carries that line's ramps, limits and communication settings.
On SINAMICS this is p0010 = 30 followed by p0970 = 1. Other manufacturers use a single reset parameter, often in a service or initialisation group. The drive typically takes several seconds and returns the parameter to zero when finished.
One caution: on drives with a fieldbus option or a safety option, a factory reset may also clear the communication address and safety configuration. Record those before resetting, and expect to reconfigure them afterwards.
Commission drives correctly the first time
Structured, hands-on VFD training covering the full parameter sequence, motor ID runs and fault diagnosis — Pune classroom or online.
Motor Nameplate Data — The Foundation
Read the values from the motor's own nameplate, not from a datasheet, a drawing or memory. Motors are rewound, replaced and substituted, and the plate on the machine is the only reliable record.
| Value | SINAMICS parameter | Notes |
|---|---|---|
| Rated voltage | p0304 | Must match the winding connection actually used — 400 V star and 230 V delta are the same motor wired differently |
| Rated current | p0305 | The single most important value; drives overload protection and the current limit |
| Rated power | p0307 | Shaft power in kW, not input power |
| Rated power factor | p0308 | Enter if the plate shows cos φ; some drives ask for efficiency instead |
| Rated frequency | p0310 | Sets base frequency and therefore where field weakening begins |
| Rated speed | p0311 | Full-load RPM, not synchronous speed — the difference is slip and the drive uses it |
| Motor connection type | Wiring plus p0304/p0305 | Verify physically in the terminal box; a star/delta mistake produces immediate overcurrent or gross underperformance |
The star/delta point causes real damage and deserves emphasis. A motor plated 400 V Δ / 690 V Y on a 400 V supply must be connected in delta. If the terminal box is strapped for star, the motor receives only 58 % of the voltage it needs, cannot produce rated torque, and the drive current-limits or trips under load. The reverse mistake — delta on a motor intended for star at that voltage — drives excessive current and can destroy the winding. Open the terminal box and confirm the links before entering a single parameter.
Also enter rated speed as the loaded figure printed on the plate, typically 1440 or 1470 RPM for a 4-pole 50 Hz motor, not the synchronous 1500. The difference is slip, and vector control uses it to build its model of the machine.
Command Source and Setpoint Source
Two independent questions the drive must be told: where does the start and stop command come from, and where does the speed reference come from. They need not be the same source, and confusing them is a frequent commissioning stall.
| Arrangement | Command source | Setpoint source | Typical application |
|---|---|---|---|
| Local | Drive keypad | Keypad potentiometer or up/down keys | Commissioning and testing only |
| Terminal control | Digital inputs from a PLC or hardwired pushbuttons | Analogue input, 0–10 V or 4–20 mA | Simple retrofits, standalone pumps and fans |
| Mixed | Digital inputs | Fieldbus | Hardwired safety-relevant start/stop with networked speed reference |
| Fieldbus | Fieldbus control word | Fieldbus setpoint word | Modern machines under full PLC control |
On SINAMICS drives the macro parameter p0015 selects a pre-built combination of these, which is faster and less error-prone than wiring up each input individually. Choose the macro that matches the installation before fine-tuning.
Prefer 4–20 mA over 0–10 V for an analogue speed reference wherever the choice exists. A current loop rejects electrical noise far better in a drive-populated panel, and the live zero means a broken wire reads as 0 mA — a detectable fault — rather than as a legitimate zero-speed command.
Limits, Ramps and Protection
| Setting | What it does | How to choose it |
|---|---|---|
| Minimum frequency / speed | Lowest speed the drive will run at | Set above zero for self-cooled motors on continuous duty; consider pump minimum flow requirements |
| Maximum frequency / speed | Highest speed permitted | Limited by the mechanical rating of the motor, gearbox and driven equipment — not by what the drive can produce |
| Ramp-up time | Seconds from zero to maximum speed | Long enough that the drive does not current-limit during acceleration; high-inertia loads need generous times |
| Ramp-down time | Seconds from maximum speed to zero | Too short causes DC bus overvoltage trips; lengthen it or add a braking resistor |
| Current limit | Maximum output current the drive will deliver | Usually 110–150 % of motor rated current; the default derived from p0305 is normally correct |
| Motor overload / thermal model | Protects the winding from sustained overload | Enable it. It is not a substitute for a thermistor on critical motors, but it is the first line of defence |
| Skip frequencies | Bands the drive passes through but will not dwell in | Set after commissioning if a mechanical resonance is found during a slow speed sweep |
Ramp times are where theory meets the machine. Set them by observation, not by preference: watch output current during acceleration and lengthen the ramp until the drive stops reaching its current limit, then watch DC bus voltage during deceleration and lengthen that ramp until the bus stops climbing toward the trip threshold. A ramp tuned this way tells you more about the load than any specification sheet.
Control Mode and the Motor Identification Run
Select the control mode only after motor data is entered, because the drive builds its internal model from that data.
For fans and centrifugal pumps, and for any case where one drive feeds several motors in parallel, choose V/f control. It is simple, robust and makes no assumption about a single specific motor.
For conveyors, mixers, extruders and anything requiring torque at low speed, choose sensorless vector control — and then perform the motor identification run. This is not optional. The drive measures stator resistance, leakage inductance and other electrical characteristics that no nameplate lists, and vector control without them is unreliable. A drive left in vector mode with an unidentified motor commonly performs worse than the same drive in plain V/f.
On SINAMICS, the identification is requested through p1900 and executed by giving the drive a run command; a stationary measurement is available where the machine cannot be rotated, and a rotating measurement gives better results where the load can be uncoupled. During the run the motor may make unusual noises and may rotate briefly — clear the area and confirm it is safe for the shaft to turn before starting.
Saving, Backing Up and Documenting
Parameters edited on the keypad live in volatile memory on many drives until explicitly saved to non-volatile storage. On SINAMICS this is p0971 = 1 (or "copy RAM to ROM" from Startdrive). A commissioning session that ends without this step is undone by the next power cycle — a genuinely common and entirely avoidable loss.
Then back up externally, using whichever the drive supports:
| Method | Advantage | Limitation |
|---|---|---|
| Memory card in the drive | A replacement unit can be cloned in minutes without a laptop | Card must be present and current; easy to forget after later changes |
| Upload to Startdrive / TIA Portal project | Stored with the PLC project, version-controlled with the machine | Needs the engineering software and someone to remember to re-upload after edits |
| Printed or exported parameter list | Readable by anyone, survives software version changes | Manual to restore |
Finally, record the non-obvious decisions somewhere the next engineer will find them: why the ramp is twelve seconds, why minimum frequency is 15 Hz, why a skip band sits at 32–36 Hz. Those choices usually encode something learned the hard way about the machine, and without a note they will be tuned back out by someone who assumes they were arbitrary.
Step-by-Step Lab: Commission a Drive from Factory Default
Hands-on- A VFD you are permitted to reset — a training rig or a bench drive, never a running production machine.
- A three-phase motor with a legible nameplate, uncoupled if possible so a rotating identification run can be performed safely.
- The drive manual or parameter list for your specific model.
- Estimated time: 45 minutes.
Record the nameplate and check the terminal box
Write down voltage, current, power, frequency, speed, power factor and the connection markings. Open the motor terminal box and confirm whether the links are strapped for star or delta.
Perform a factory reset
On a SINAMICS drive set p0010 = 30 then p0970 = 1, and wait for the drive to finish. On other makes, use the equivalent reset parameter from the manual.
Enter quick commissioning and the motor data
Set p0010 = 1 to enter quick commissioning, then enter p0304, p0305, p0307, p0308, p0310 and p0311 from your recorded nameplate values.
Select the macro and set ramps
Choose the connection macro matching your setup (p0015), then set ramp-up and ramp-down to a deliberately conservative ten seconds each.
Run the motor identification
Exit quick commissioning, request the identification run with p1900, then give the run command and let the drive complete its measurement.
Tune the ramps against the real load
Run to full speed while watching output current, then stop while watching DC bus voltage. Shorten each ramp progressively until you see the drive current-limit on acceleration or the bus climb on deceleration, then back off.
Save and back up
Save the parameter set to non-volatile memory (p0971 = 1), power-cycle the drive, and verify the settings survived. Then export the parameter set to a memory card or engineering project.
The commissioning is sound if the drive starts and stops cleanly, does not current-limit during a normal start, does not trip on overvoltage during a normal stop, and holds every setting through a power cycle. If any of those fails, the cause is nearly always in the order the parameters were entered — go back to the factory reset and repeat the sequence rather than adjusting individual values.
Frequently asked questions
In what order should VFD parameters be set?
Factory reset, then motor nameplate data, then command and setpoint source, then limits and ramps, then control mode, then the motor identification run, then save and back up. The order matters because the drive derives current limits, protection thresholds and its internal motor model from the nameplate data — entering that data later overwrites values you set earlier.
Why does the motor connection type matter so much?
A motor plated 400 V delta / 690 V star running from a 400 V supply must be wired in delta. Strapped for star it receives only 58 % of the required voltage and cannot produce rated torque. The opposite error drives excessive current and can destroy the winding. Always verify the links in the terminal box before entering parameters.
Do I really need to run a motor identification?
For sensorless vector control, yes. The drive needs stator resistance and leakage inductance values that no nameplate provides, and vector control without them typically performs worse than plain V/f. For V/f control on a fan or pump, the identification run is not required.
What ramp times should I use?
Set them by observation on the actual load. Shorten the acceleration ramp until the drive begins to current-limit, then back off. Shorten the deceleration ramp until DC bus voltage starts climbing toward the trip threshold, then back off. High-inertia loads need generous times or a braking resistor.
My settings disappeared after a power cycle. What happened?
They were held in volatile memory and never written to non-volatile storage. On SINAMICS drives, set p0971 = 1 — or use the copy RAM to ROM function — at the end of every commissioning session, then power-cycle and verify before leaving the machine.
Should I use 0–10 V or 4–20 mA for the speed reference?
Prefer 4–20 mA. A current loop is far more immune to the electrical noise present around drives, and the live zero means a broken wire reads as 0 mA and can be detected as a fault, whereas a broken 0–10 V wire simply reads as a valid zero-speed command.