IC-PI datasheet(29/49 Pages) ICHAUS

29 / 49 page

preliminary

iC-PI PROGRAMMABLE 12-BIT

Sin/Cos INTERPOLATION IC WITH RS422 DRIVER

Rev B1, Page 29/48

SIGNAL CONDITIONING CH0

Input Mode CH0

DUAL configures the channel CH0 to process either

analog or digital input signals.

DUAL

Addr. 0x07, bit 7

Code

Mode

0x0

Analog input function

0x1

2-bit digital input function

Table 32: Dual Input Mode

When the inputs are configured to analog (DUAL = 0),

the gain and offset signal conditioning parameters de-

scribed further below are operational.

When configured for digital signals (DUAL = 1), the in-

puts X1 (for PCH0) and X2 (for NCH0) evaluate a 2-bit

Gray-coded multiturn signal. Using this code, the re-

peated signal cycles generated by a magnetoresistive

angle sensor or an optical polarization sensor can be

distinguished.

To do so, iC-PI interprets the upper bit on X1 (PCH0) as

period information, and uses the lower bit on X2 (NCH0)

to synchronize the multiturn information to the internal

angle position derived form the sine/cosine signals of

CH1 and CH2.

Gain Settings CH0

For analog input mode (DUAL = 0), the test signals

required to calibrate the zero channel are available in

mode Calibration 1.

Additionally, the relative phase of the ungated zero sig-

nal ZIn compared to A and B can be determined in mode

System Test.

The CH0 gain is set using the following steps:

1. The signal level control is to be shut down and the

constant current source for the ACO output is set to the

same values as during the calibration of CH1 and CH2

(registers ACOT, ACOR and ACOS).

2. The coarse gain is to be selected so that a differential

signal amplitude of approx. 1 Vpp is produced internally

(signal PCH0 to NCH0).

3. GF0 then permits fine gain adjustment to 1 Vpp. The

total gain is GR0 x GF0.

GND

0.25 Vp

1 Vpp

0.25 Vp

pk(Nx)

pk(Px)

peak-to-peak

Calibration 1

iC-PI

Figure 15: Definition of 1 Vpp differential test sig-

nal. Note that the outputs should not be

loaded during Test and Calibration modes

(R0 must be high resistance).

Note: Using mode Test 5 is not recommended, as the

CH0 outputs are not buffered.

GR0

Addr. 0x07, bit 6:4

Code

Factor with input voltage

divider (R0 = 0x9)

Factor w/o input voltage

divider (R0 ̸= 0x9)

0x0

0.5

2.0

0x1

1.0

4.1

0x2

1.3

5.3

0x3

1.7

6.7

0x4

2.2

8.7

0x5

2.6

10.5

0x6

3.3

13.2

0x7

4.0

16.0

Notes

The effective total gain is calculated using:

G0eff = GF0 x GR0, or

G0eff = 1/4 x GF0 x GR0

if using the input voltage divider (R0 = 0x9).

Table 33: Coarse Gain Factor CH0

GF0

Addr. 0x08, bit 4:0

Code

Factor

0x00

1.00

0x01

1.06

...

6.25

GF0

0x1F

6.25

Table 34: Fine Gain Factor CH0

IC-PI Datasheet(PDF) 29 Page - IC-Haus GmbH

IC-PI Datasheet(HTML) 29 Page - IC-Haus GmbH

Html Pages

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49

Datasheet Download

Link URL