HIMA HIMatrix F3 AIO 8/4 01, Руководство пользователя

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F3 AIO 8/4 01 3 Product Description
HI 800 161 E Rev. 2.00 Page 15 of 56
2. Short-Circuit:
An short-circuit within the actuator circuitry (including the actuator) results in a high voltage drop
(

output voltage of DO) through the shunt, which causes the short-circuit to be detected
(maximum resolution of AI, see Table 7). The overvoltage protection of the analog inputs is
activated at approximately 15 V.
A protective circuit consisting of a Z-diode and series resistor must be implemented to avoid an
overload of the internal overvoltage protection.
NOTE
To protect the input multiplexer of the analog inputs from overload, a protective circuit
consisting of Z-diode and a series resistor must be connected within the input circuit in
parallel to the existing shunt
The configuration of the Z-diode with series resistor depends on the overvoltage protection
threshold and must be set up to ensure that the HIMatrix overvoltage protection is not activated
if a short-circuit occurs.
Configuration example for short-circuits:
Shunt: R
shunt
10

Solenoid valve resistance: R
solenoid valve
75

Maximum output voltage of the digital output DO U
max
26.8 V
Table 8: Example of Short-Circuit

Z-diode with switching voltage of 12 V
 Analog input with operating range of 0...10 V

Overvoltage protection in the HIMatrix with input voltage > 15 V
Normal operation (no short-circuit):
U
max
= U
solenoid valve
+ U
shunt
= 26.8 V = 23.65 V + 3.15 V
The voltage U
shunt
is also present on the protective circuit consisting of Z-diode and series
resistor.
The Z-diode does not switch on at 3.15 V, i.e., the voltage drop of 3.15 V on the shunt is
present on the analog input.
Short-circuit:
U
max
= U
solenoid valve
+ U
shunt
= 26.8 V = 0 V + 26.8 V
If a short-circuit occurs in the external circuit (actuator or line), the voltage from DO is dropped
completely at the shunt.
The switching threshold of the overvoltage protection of AI is approximately 15 V.
The Z-diode should become conductive at 12 V such that no more than 12 V is present on AI
and the entire scaling range of AI is available.
The maximum voltage drop U
diode
on the series resistor R
diode
of the Z-diode results from:
U
diode
= 26.8 V – 12 V = 14.8 V