A patented variant of the SMALL-Ex® measuring instrument detects the temperature flank and compares this with the temperature gradients which are stored by the manufacturer such as those at a belt start-up at the cheek of a conveyor belt. For this version the level of the environmental temperature is irrelevant to the detection and does not affect the evaluation. With this temperature switch, a differential temperature of 20 ° K and a difference time of 10 seconds are usually set. This means that when the temperature changes more than 20 ° K within less than 10 seconds, a slanting of the conveyor belt is detected. As long as the temperature rise is not exceeded and the time is not missed at the same time, the system is in normal operation.
At normal operating the instrument sends a constant signal of e.g. 5 ma (or 7 Hz). If the temperature increases above the normal operating temperature, e.g. a 19 ma (or 14 Hz) signal is sent. The recognition of the danger occurs in the instrument, not in the control system. Furthermore, a warning temperature (e.g. 40 °C) with e.g. 12 ma (or 10 Hz) and a maximum temperature ( e.g. 60 °C) with e.g. 17 ma (or 13 Hz) will be transmitted. These values are variable and can be set beforehand.
To ensure the safety switch, the instrument occurs a self-test which occurs discretly by restarting the instrument, by a set time interval for an alternating signal of e.g. 9 ma (or 9Hz) and 15 ma (or 12 Hz) transmitted. This self-test occures at every restart and can be triggered manually on site or externally.
Moreover, a further variant of montoring and transmitting is possible. In normal operating the instrument sends a „1“ signal. If the dangerous temperature rise for the system is detected, the instrument sends a „0“ signal.
On demand the self-test can be done out from outside by a magnetic switch or the measuring instrument can be acknowledged if the limit value has been exceeded.
I Ex ia I Ma
Ex ia I Ma
PO Ex ia I Ma X
BVS 06 ATEX E005 X
IECEx BVS 09.0056X
IECEx TSA 13.0023X
MSHA 18-ISA 150004-0
TC RU C-DE.MЮ62.B.03774
MA J2012330, J2012329
-50 to +100 °C bei Gruppe I
-50 to +80 °C bei Gruppe II
+/- 1% from end-value (higher accuracy on request)
fluid and gaseous media as well as surfaces
+/- °C, +/-°F (other units on reauest)
customized output signals with intermediate ranges configurable on request
12V DC (7,5 – 14,0 V DC) 3-wiring technology
16V DC (9,6 – 16,1 V DC) 3-wiring technology
24V DC (14 – 26,6 V DC) 2-wiring technology