Many customers often ask about the different types of Speed Feedback available in the DC590 drive: what types are there, how they are structured and operate, and the advantages & disadvantages of each.
Today, let’s explore in detail the 3 types of Speed Feedback in the DC590.
1. ARM VOLTS FBK
This is the default Speed Feedback type of the DC590 drive.
Structure & Operation
The DC590 already has this feedback circuit built in. When the drive operates, the voltage from terminals A+ and A- is fed back to the controller as the Speed Feedback signal.
Advantages
- No additional hardware wiring required
- Easy to use
- Minimizes faults from external devices (Option Card, Encoder, Tachometer)
- Cost-effective
Disadvantages
- Only open-loop feedback → cannot meet high-precision applications
- Not applicable for Field Weakening mode
- Not suitable for applications requiring high accuracy
2. ANALOG TACHOMETER
Structure & Operation
A tachometer is usually mounted at the rear of the DC motor. When the motor rotates, the tachometer shaft generates a voltage proportional to the speed.
Example: 30VDC/1000rpm → at 1000 rpm, it outputs 30VDC.
Wiring on Option Card
- DC Tachometer: connect to G3 & G4, switch set to DC.
- AC Tachometer: connect to G1 & G2, switch set to AC.
Advantages
- Closed-loop speed feedback (from actual motor speed)
- Simple installation & wiring
- High durability
- Suitable for high-accuracy applications, supports Field Weakening mode
Disadvantages
- Tachometer generators are uncommon and hard to source in the market
Setup
– In DC590: select SPEED FBK SELECT = ANALOG TACH
– On Option Card: set the switch according to Vmax voltage corresponding to the required maximum speed.
Example: Motor 1500 rpm with tachometer 30VDC/1000 rpm → Vmax = 45V.
3. ENCODER
Structure & Operation
An encoder converts rotary motion into digital signals/pulses.
It is a common and widely used device in many applications.
Hardware Wiring
- E1 – 0VDC
- E2 – Supply DC (Isolated)
- E3 – A Channel
- E4 – A Complement
- E5 – B Channel
- E6 – B Complement
Advantages
- Accurate closed-loop speed feedback
- Widely available in the market, a replacement solution for tachometers
- Ideal for demanding applications, supports Field Weakening
Disadvantages
- Almost none
Setup in DC590
– SPEED FBK SELECT = ENCODER
– ENCODER LINES = encoder resolution
– ENCODER RPM = maximum motor speed
– Option Card: adjust encoder supply voltage (5VDC – 24VDC)
