GHM Martens TB225, Руководство по эксплуатации

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GHM Group
– Martens
GHM Messtechnik GmbH | Kiebitzhörn 18 | 22885 Barsbüttel | Germany
Phone +49-40-670 73-0 |
info@ghm-group.de
| www.ghm-group.de
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5 Functional Safety
The temperature limiter TB225 was developed according to the specifications of IEC 61508.
This standard describes the functional safety of safety-related programmable electrical and
electronic systems.
The device corresponds to a class B subsystem with a requirement level of SIL2 (single-
channel). The safety function of the device refers to measurement and evaluation of the
temperature and the resulting contact position of the built-in relay.
Safe Condition
The safe condition of the device is given only in the resting position of the main relay (cur-
rent principle). If the internal diagnostic system detects an error, the main relay assumes
the resting position. For the integration of the relay changer into the monitoring system,
therefore the closing contact must be used.
Temperature Sensor
Connected temperature sensors are monitored for open circuit or short circuit. In the case
of using thermocouples, this is physically only possible with double thermocouples. It is not
permitted to use single thermocouples and set the inputs parallel by wire bridges. If sepa-
rate sensor fittings are used, they must be mounted directly next to each other so that both
can reach the same temperature.
Fault and Error
If there is an accident at the plant, the cause must be eliminated immediately. If the tem-
perature limiter TB225 is decommissioned, the process must be secured in a different way.
If there is a device error, we kindly ask you to send it to the factory with a short description
of the error.
Safety key figures for functional safety TB225
Attention: Only for the device variant with SIL approval!
Safety-related output signal relay output
Test standard IEC 61508
Testing laboratory TÜV NORD CERT GmbH
Safety integrity SIL 2
System Typ B
Input
Pt100 Thermocouple 4 .. 20mA 2 .. 10V
λ
SD
(Rate of detected safe failures) 88 FIT 73 FIT 71 FIT 71 FIT
λ
SU
(Rate of undetected safe failures) 524 FIT 486 FIT 505 FIT 506 FIT
λ
DD
(Rate of detected dangerous failures) 325 FIT 311 FIT 279 FIT 279 FIT
λ
DU
(Rate of undetected dangerous failures) 658 FIT 606 FIT 620 FIT 620 FIT
(1 FIT = 1 failure / 10
9
h)
Average probability of failure on demand (PFD
avg
) 6,46 x 10
-3
3,95 x 10
-3
4,81 x 10
-3
4,78 x 10
-3
Probability of failure per hour (PFH) 1,55 x 10
-7
9,81 x 10
-8
1,18 x 10
-7
1,17 x 10
-7
Useful life of the safety function 10 years 10 years 10 years 10 years