A PG card is the feedback link between an encoder and a closed-loop drive: it tells the drive exactly where the motor is, so the car levels precisely and holds at zero speed. Open-loop drives do not use one; closed-loop drives cannot run properly without a matched one.
What Is a PG Card?
A PG card, also called a PG feedback card, is the interface that carries encoder signals into an elevator drive. An encoder is a sensor fitted to the motor that reports speed and position as the motor turns. Together, the encoder and the PG card close the loop: the encoder measures, the PG card delivers that measurement to the drive, and the drive adjusts its output to keep speed and position under control.
Why Precise Levelling Depends on Feedback
Precise levelling and zero-speed hold depend on feedback. Without a measured position, a drive can only estimate where the car is; with feedback, it can correct continuously as the car approaches a floor and hold it still once it stops. The 11LIFT manual figures show the gap — closed-loop FVC holds 0Hz at 200% torque with ±0.05% precision, against open-loop SVC at ±0.5%. That difference is what passengers feel as a car that stops level, rather than one that stops short or creeps.
When Do You Need a PG Card?
A PG card is needed for closed-loop upgrades and retrofits, where feedback is part of the control method. It is not needed for a like-for-like open-loop replacement, because an open-loop drive controls the motor without encoder feedback. If you are changing control method, rather than only changing a failed unit for the same type, the PG card becomes part of the job. See the comparison in the open-loop vs closed-loop elevator drive article before deciding which route your lift needs.
Where Is a PG Card Fitted?
A PG card is fitted in the machine room, to the drive, and matched to the motor’s encoder type. It is not a car-top or shaft item: it sits with the drive electronics, where its wiring and parameter settings can be checked during commissioning. Matching matters here, because different encoder types need different PG card types, and a mismatch can leave the drive unable to read the motor correctly.
How to Match and Commission a PG Card
- Confirm the drive type: open-loop or closed-loop.
- Identify the encoder type fitted to the motor.
- Match the PG card to that encoder type; the replacement article notes the PG card is priced separately and matched to encoder type.
- Check wiring and parameter entry against the motor nameplate.
- Commission floor by floor: auto-tuning, travel curve setup, levelling adjustment on every floor, as the replacement article’s How section sets out.
- If the old encoder is healthy and compatible with the chosen PG card, it can be reused; compatibility must be confirmed, not assumed.
For the wider job around a replacement, read the elevator inverter replacement article and the closed-loop elevator drive commissioning checklist. For scope and matching questions, see also the closed-loop elevator drive cost, encoder and PG card article.
Open-Loop vs Closed-Loop
| Open-loop | Closed-loop | |
|---|---|---|
| Feedback | None, no PG card | Encoder plus PG card |
| Levelling precision | ±0.5% (SVC) | ±0.05% (FVC) |
| Zero-speed hold | No | Yes, 0Hz at 200% torque |
Do I Need a PG Card?
| Situation | PG card? |
|---|---|
| Open-loop drive, like-for-like replacement | No |
| Closed-loop upgrade (D3300 or 11LIFT closed-loop) | Yes, matched to the encoder |
| Reusing an old encoder | Only if healthy and compatible |
Frequently Asked Questions
What does a PG card actually do?
It carries encoder feedback to the drive for precise speed and position control.
Can a closed-loop drive run without a PG card?
No: without feedback it cannot hold position or level precisely.
Is the PG card included in the drive price?
It is often priced separately and matched to encoder type, so check the quote scope.
If my lift levels badly, will a new PG card alone fix it?
Not necessarily: tuning, encoder health and mechanical condition also decide levelling, so check those first.
Can I reuse my old encoder with a new PG card?
Yes, if it is healthy and compatible with the chosen PG card; compatibility must be confirmed, not assumed.
To check whether your lift needs a PG card, send the drive model and encoder type for a PG card match check. For a closed-loop option, see the 11LIFT closed-loop elevator inverter.