Stahl 9170 1 Series, Manual

Page: 32 / 43

Operation
12
200089 / 9170612310
2020-04-30·BA00·III·en·09
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
EN
Switching repeater
Series 9170/.1
8 Operation
8.1 Operation
Operating principle
The switching repeater assesses a digital signal from an intrinsically safe circuit. It transmits
the switching state of its input to the output. Various output variants with signal relay,
power relay or electronic output are available.
The switching repeater checks if there are line faults (wire breakage and line short circuit)
in the electrical lines between the switching repeater and field device. If an error is detected,
this will be output in the form of a collective error message. The corresponding switching
outputs enter a de-energised state. Type 9170/.1-14-12 features line fault transparency.
This function allows the message regarding the line faults to be transmitted to the
downstream control level directly via the signal channel.
Operating states
Input Signal Output state in case of
"inverted direction of action" (INV1/2)
OFF
ON
line fault detection LF = deactivated (LF1/2 = "OFF")
Initiator
high-impedance/
contact is opened/
wire breakage
I
E
(
1.2 mA Relay is not
energised/
electronic output
blocks
Relay is energised/
electronic output
conducts
Initiator
low-resistance/
contact is closed/
short-circuit
I
E
)
2.1 mA Relay is energised/
electronic output
conducts
Relay is not
energised/
electronic output
blocks
line fault detection LF = activated (LF1/2 = "ON")
Wire breakage
I
E
(
0.05 to 0.35 mA Relay is not
energised/
electronic output
blocks
Relay is not
energised/
electronic output
blocks
Initiator
high-impedance /
contact is opened
I
E
= 0.35 to 1.2 mA Relay is not
energised/
electronic output
blocks
Relay is energised/
electronic output
conducts
Initiator
low-resistance /
contact is closed
I
E
= 2.1 to 5 mA Relay is energised/
electronic output
conducts
Relay is not
energised/
electronic output
blocks
Short circuit R
E
< 100 to 360 Ω Relay is not
energised/
electronic output
blocks
Relay is not
energised/
electronic output
blocks
The types 9170/.1-14-12 transmit the input signals at the output in a different way than
the way described in the table above (see Chapter 6.2.1).