1 function of increased safety, 2 application in the 1-sensor variant, 3 application in the 2-sensor variant – JUMO 14597 safetyM STB/STW Ex - Safety Temperature Limiter and Safety Temperature Monitor Operating Manual User Manual
Page 85: Function of increased safety, Application in the 1-sensor variant, Application in the 2-sensor variant, 7 atex
7 ATEX
79
7.5.1
Temperature monitoring unit based on ignition protection "e" – increased safety according to
EN 60079-7
7.5.1.1
Function of increased safety
Ignition protection for which additional measures are taken in order to use an increased degree of safety to prevent the possi-
bility of the occurrence of inadmissibly high temperatures or sparks or electric arcs at or in parts of electrical apparatus where
these would not occur in standard operation.
7.5.1.2
Application in the 1-sensor variant
As shown in Table 1: "Achievable SIL"
in Chapter 6.6 "Connection possibilities of the sensors (SIL)" of this Operating Manual,
the JUMO safety
M STB/STW Ex evaluation unit is always structured in the same way and its architecture always has a 1oo2D
structure. If only one passive sensor is connected, this corresponds to variant 1 of Table 1: "Achievable SIL" in Chapter 6.6
"Connection possibilities of the sensors (SIL)".
According to Chapter 6.9.2 "Safety-relevant system features" in this Operating Manual, the "sensor system" subsystem there-
fore has a 1oo1 architecture and an HFT of 0. In conjunction with the monitored apparatus as combined apparatus, this variant
therefore meets the safety requirements according to EN 50495 for systems that are used in category 2 (zone 1) if the moni-
tored apparatus does not represent an ignition source in standard operation. The requirements in Table 1 of EN 50495 apply.
The limit value must be determined according to the relevant use and/or application. The value must be set so that no danger-
ous state can occur when all relevant factors such as response time and, if applicable, temperature overshoot of the monitored
apparatus including the JUMO safety
M STB/STW Ex are taken into account.
To prevent unintended changes to the set parameters, the JUMO safety
M STB/STW must be sealed according to Chapter 5.8
of this Operating Manual or a keypad lock or level inhibit must be used according to Chapter 8.4.
7.5.1.3
Application in the 2-sensor variant
If two passive sensors are connected, this corresponds to variants 1a, 2, 3, and 4 of Table 1: "Achievable SIL"
"Connection possibilities of the sensors (SIL)". According to Chapter 6.9.2 "Safety-relevant system features" in this Operating
Manual, the "sensor system" subsystem therefore has a 1oo2 architecture and an HFT of 1. In conjunction with the monitored
apparatus as combined apparatus, these variants therefore meet the safety requirements according to EN 50495 for systems
that are used in category 1 (zone 0) if the monitored apparatus does not represent an ignition source in standard operation. The
requirements in Table 1 of EN 50495 apply.
The limit value must be determined according to the relevant use and/or application. The value must be set so that no danger-