JUMO 701150 14597 safetyM STB/STW - Safety Temperature Limiter and Safety Temperature Monitor Operating Manual - Manual (Page 32)

6 Safety Manual 2014-05-01 32
6 Safety Manual
6.1 Brief description
The safety temperature limiter (STB) and safety temperature monitor (STW) enable early and reliable detection of risks which
could potentially result in personal injuries, environmental damage, or destruction of the production plant and production mate-
rials.
Its task is to reliably monitor process variables such as temperature or pressure and to switch the plants to an operationally
safe status in the event of malfunctions.
The measured value at the analog input can be recorded by various probes or standard signals.
Even when using double sensors (1oo2) only one physical measuring point is monitored at the measuring point.
Limit value exceedance is indicated by the installed LED K1 and K2 (red) for each channel and the integrated alarm relay
switches the system to safe operating status (alarm range).
The SIL3 requirements of DIN EN 61508 or PLe DIN EN ISO 13849 are met by a device concept that has a 1oo2D structure
which ensures reliable detection of errors.
6.2 Safety temperature monitor (STW)
The safety temperature monitor is a device that is automatically reset when activated once the sensor temperature has fallen
below or risen above the set limit value by an amount equal to the switching differential. Possible settings: monitoring for limit
value overrange or underrange.
Mode of operations:
-
Minimum requirements: 2B, 2K, 2P
- Additional requirements: 2N, 2D
6.2.1 Safe operating status STW
The safe status is when the relay output alarm between terminals 14 and 16 is switched off (closed-circuit principle).