IC-MSB Datasheet, PDF (27/29 Pages) IC-Haus GmbH – SIN/COS SIGNAL CONDITIONER WITH 1Vpp DRIVER

iC-MSB^SAFETY, iC-MSB2
SIN/COS SIGNAL CONDITIONER WITH 1Vpp DRIVER
APPLICATION HINTS
Rev D2, Page 27/29
Connecting MR sensor bridges for safety-related applications
For safety-related applications iC-MSB^SAFETY requires an external overvoltage protection of supply VDD (Zener
diode with fuse, for instance) and external pull-down resistors at the inputs X3 to X6 towards GNDS (of up to
100 kΩ).
VP
SCL
24xx
SDA
VN
R5 R6
2.2kS 2.2kS
C1
100nF
SCL
SDA
VDDS
VDD
I²C
iC-MSB
ACO
SIGNAL
LEVEL
CONTROL
ERR
C2
100nF
PZ
MR0
MR1
MR2
X1
+
- ^X2
INPUT ZERO
X3
X5
R1
R2
100kS 100kS
+
-
INPUT COS
X4
X6
R3
R4
100kS 100kS
+
-
INPUT SIN
GNDS
NZ
PC
NC
PS
NS
GND
F1
D1
5.6V
+5V
ERR
RL
100S
RL
100S
RL
100S
0V
TVS diode array
Figure 7: Example circuit for safety-related applications with iC-MSB^SAFETY .
PLC Operation
There are PLCs with a remote sense supply which re-
quire longer for the voltage regulation to settle. At the
same time the PLC inputs can have high-impedance
resistances versus an internal, negative supply voltage
which define the input potential for open inputs.
In this instance iC-MSB’s reverse polarity protection
feature can be activated as the outputs are tristate dur-
ing the start phase and the resistances in the PLC de-
termine the pin potential. During the start phase nei-
ther the supply VDD nor the output pins, which are
also monitored, must fall to below ground potential (pin
GND); otherwise the device is not configured and the
outputs remain permanently set to tristate.
In order to ensure that iC-MSB starts with the PLCs
mentioned above pull-up resistors can be used in the
encoder. Values of 100 kΩ are usually sufficient; it
is, however, recommended that PLC specifications be
specifically referred to here.