6 Safety Manual
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6.3.4 Issue of an error signal (safe state)
In SIL operation, the measured value at the analog input is always issued at the analog output 4 to 20 mA.
The limit values according to Namur NE 43 (≤ 3.6 or ≥ 21 mA) are only issued when internal errors, probe errors, or a limit value
monitoring function (extra code) are identified.
6.4 Relevant standards
Type 707071 SIL fulfills the requirements for SIL 2, or SIL 3 in redundant use, according to DIN EN 61508 and PL c/PL d ac-
cording to DIN EN ISO 13849-1, as well as the requirements of DIN EN 60730-2-9.
The systematic suitability is defined at SC = 3 for HW and SW.
This means that SIL 2 or PL c for HFT = 0 (individual device) and SIL 3 or PL d for HFT = 1 (2 devices) are achieved.
For the safety function up to SIL 3 according to DIN EN 61508 Part 1 to 7:
Functional safety of electrical/electronic/programmable electronic safety-related systems
DIN EN 60730-2-9:
Automatic electrical controls for household and similar use – Part 2-9: Particular requirements for temperature sensing controls
DIN EN ISO 13849-1:
Safety of machinery - Safety-related parts of control systems
DIN EN ISO 13849-2:
Safety of machinery - Safety-related parts of control systems - Part 2: Validation (ISO 13849-2)
6.5 Connection possibilities of the sensors
Variant connected Sensors
Variant 1 RTD temperature probe in a 2-, 3- or 4-wire circuit
Variant 2 double thermocouple
Variant 3 4 to 20 mA
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