IC-MQ_15 Datasheet, PDF (22/43 Pages) IC-Haus GmbH – Sin/Cos INTERPOLATION IC WITH RS422 DRIVER

iC-MQ PROGRAMMABLE 9-BIT
Sin/Cos INTERPOLATION IC WITH RS422 DRIVER
SIGNAL CONDITIONING CH1, CH2
Rev F3, Page 22/43
The analog voltage signals necessary for the calibra-
tion of the sine signals can be measured in operation
mode Calibration 2. Alternatively, characteristic digital
test signals are also available for offset, amplitude and
phase errors in operating mode System Test.
Gain Settings
The gain is set in four steps:
1. The sensor supply controller is shut down and the
constant current source for the ACO output set to a suit-
able output current (register ADJ; current value close
to the later operating point).
2. The coarse gain is selected so that differential signal
amplitudes of ca. 1 Vpp are produced internally (signal
Px versus Nx, see Figure).
3. Using fine gain factor GF2 the CH2 signal amplitude
is then adjusted to 1 Vpp.
GR12
Code
0x0
0x1
0x2
0x3
0x4
0x5
0x6
0x7
GF2
Code
0x00
0x01
...
0x1F
4. The CH1 signal amplitude can then be adjusted to
the CH2 signal amplitude via fine gain factor GF1. This
results in a total gain of GR12 * GFi for differential input
signals.
GF1
Code
0x00
0x01
...
0x7F
Addr 0x04, bit 2:0
Range RIN12=0x9
0.5
1.0
1.3
1.7
2.2
2.6
3.3
4.0
Range RIN12̸=0x9
2.0
4.1
5.3
6.7
8.7
10.5
13.2
16.0
Table 23: Gain Range CH1, CH2
Addr 0x04, bit 7:3
Factor
1.00
1.06
GF2
6.25 31
6.25
Table 24: Fine Gain Factor CH2
Addr 0x06, bit 2:0, Addr 0x05, bit 7:4
Factor
1.0
1.015
GF1
6.25 124
6.53
Table 25: Fine Gain Factor CH1
Px
VPx
Nx
VNx
GND
R0
VPNx
Figure 7: Definition of 1 Vpp signal. Termination R0
must be high-ohmic during all Test and
Calibration modes.