C.2.2, Alarm operation using the 0-20ma signal current, C.2.3 – Spectrex Xenon 700 SIL Open-Path Gas Detection System User Manual

Page 74: Relay outputs, Miscellaneous, C.3 miscellaneous, C.2.3 relay outputs

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SafEye

TM

Xenon 700S SIL Gas Detector

62

Miscellaneous

C.2.2 Alarm Operation using the 0-20mA Signal Current

The connected controller has to monitor the 0-20mA signal current for valid
values: (see cap. Output Signals)


Mode

Normal

Warning

Alarm

Continuous current
with low sensitivity

(Full Scale: 5 LEL.m)

4 mA
(0 LEL.m)

7.2 mA
(1 LEL.m)

13.6 mA
(3 LEL.m)

Continuous current
with high sensitivity

(Full Scale: 2 LEL.m)

4 mA
(0 LEL.m)

7.2 mA
(0.4 LEL.m)

12 mA
(1 LEL.m)

Discrete current

4 mA

14 mA

19 mA

The connected controller has to monitor the 0-20mA signal current for
values below 4mA and above 20mA.

C.2.3 Relay Outputs

Relay outputs don’t comply with SIL2 requirements.

C.3

Miscellaneous

The complete functional performance of the gas detector has to be verified
half-yearly (gas detection, fault detection, performance of the 0-20mA
signal current and the relays), gas alarms ON and OFF.
The HART® and RS 485 interface are not allowed to be used for the
transmission of safety related data.

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