Power Brick Controller User Manual
Connections and Software Setup
37
Configuring Quadrature Encoders
The Power Brick Controller default settings are configured for quadrature encoders. Minimal setup is
required to configure them; quadrature encoder signals are processed as a single 32-bit read in the encoder
conversion table (ECT). 1/T extension is done in the Gate3 "hardware".
The default ECT settings for an incremental quadrature encoder look like:
Note
The hardware 1/T extension produces 8 bits of fractional data, thus
the (1 / 256) 0.00390625 scale factor.
Channel
Number
Quadrature Encoder
Source Address
Channel
Number
Quadrature Encoder
Source Address
1
PowerBrick[0].Chan[0].ServoCapt.a
5
PowerBrick[1].Chan[0].ServoCapt.a
2
PowerBrick[0].Chan[1].ServoCapt.a
6
PowerBrick[1].Chan[1].ServoCapt.a
3
PowerBrick[0].Chan[2].ServoCapt.a
7
PowerBrick[1].Chan[2].ServoCapt.a
4
PowerBrick[0].Chan[3].ServoCapt.a
8
PowerBrick[1].Chan[3].ServoCapt.a
Activating the corresponding channel is sufficient to display counts in the position window when the motor
/ encoder shaft is moved by hand.
The position and velocity source(s) must be pointing to the proper ECT result. With quadrature encoders,
they are initiated by the firmware:
Counts per User Units
With quadrature encoders, the number of counts per user units (usually revolution) is 4 times the specified
number of lines of the encoder. For example, a 1,000–line rotary encoder should result in 4,000 motor units
per revolution.
EncTable[
1
].type =
1
// Single 32-bit read
EncTable[
1
].pEnc = PowerBrick[
0
].Chan[
0
].ServoCapt.a
// Primary source, ch 1 Servo Capture
EncTable[
1
].pEnc1 = Sys.Pushm
// Secondary source, none
EncTable[
1
].index1 =
0
// left shift, none
EncTable[
1
].index2 =
0
// right shift, none
EncTable[
1
].index3 =
0
//
EncTable[
1
].index4 =
0
//
EncTable[
1
].ScaleFactor =
1
/
256
// Scale Factor, LSB location
Motor[
1
].ServoCtrl =
1
// Channel activation
Motor[
1
].pEnc = EncTable[
1
].a
// Position
Motor[
1
].pEnc2 = EncTable[
1
].a
// Velocity
