Actual Position Configuration Based On A Motor Encoder Signal; Position; Example - ABB ACS800 Firmware Manual

Actual position configuration based on a motor encoder signal

Position

The Position function calculates the actual position of the hook. The Shaft synchro
function uses the hook position when synchronising the Master and Follower drives.
In addition, the position is used in anti-sway controlled trolley drives and long travel
drives. The position is based on the encoder on the motor shaft. To enable the
position calculation, you must define the factor that scales the encoder pulse to
actual position units. See the following example.
The actual position value
power is switched off/on in the RMIO board.

Example

If the hoist drive operates at 40 000 mm/min corresponding to the motor speed of
1500 rpm, and the encoder parameter
parameter
mm. The POS SCALE in pulses/mm can be calculated by multiplying the motor
speed with the PPR and then dividing with the corresponding linear speed. The
linear speed can be calculated using the equation shown in section
linear rope speed
linear speed of 13333.33 mm/min, then the POS SCALE would be ((500 * 2048) /
13333.33) = 76.8 pulses/mm. The Shaft synchro function uses the actual position in
the Master and Follower drives. That is why you should use the same measurement
unit for the scaling factor in both drives, that is, mm.
If the parameters (gearbox ratio, diameter) used for calculating the linear speed are
not available, the position scale can be calculated by the following procedure.
1. Set the encoder PPR in parameter
2. Monitor the shaft position signal
and note the shaft position signal
3. Start the drive and stop it after a few mm travel of the rope.
4. Check the shaft position signal
Suppose the initial value in shaft position
2000, and this motion has resulted in the rope travel of 20 mm, then the position
scale would be (2000 / 20) = 100 P/mm.
Note: The value range of actual position
+8388608, but when the value is used in the fieldbus for data transfer, it is truncated
to -32767 to +32767.
02.21
78.04 POS SCALE value equals to ((1500*2048) / 40 000) = 76.8 pulses/
on page 103. If the motor speed is 500 rpm, which corresponds to
POS ACT PPU is saved in the memory after the
50.01 PULSE NR ppr is set to 2048,
50.01 PULSE NR.
02.22 SHAFT POS, mark the rope with a marker
02.22 SHAFT POS.
02.22 and the corresponding travel in mm.
02.22 was zero, after stopping it shows
02.21 POS ACT PPU is -8388608 to
91
Calculating the
Program features