2-channel thermocouple input terminal with open-circuit recognition EL3312
Error LED 2
Error LED 1
Run LED2 
Run LED1 
Power contact
+24 V
Power contact 0 V
+TC1
+TC2
GND
Shield
-TC1
-TC2
GND
Shield
Top view 
Contact assembly 
Observe for earthed
thermocoupler:
differential inputs
max. ± 2 V to ground
extended temperature range
extended shock and vibration range

EL3312 | 2-channel thermocouple input terminal with open-circuit recognition

The EL3312 analog input terminal allows thermocouples to be connected directly. The EtherCAT Terminal's circuit can operate thermocouple sensors using the 2-wire technique. Linearisation over the full temperature range is realised with the aid of a microprocessor. The temperature range can be selected freely. The error LEDs indicate a broken wire. Compensation for the cold junction is made through an internal temperature measurement at the terminal. The EL3312 can also be used for mV measurement.

Technical data EL3312
Number of inputs 2
Power supply via the E-bus
Thermocouple sensor types types K, J, L, E, T, N, U, B, R, S, C (default setting type K), mV measurement
Distributed clocks
Input filter limit frequency typ. 1 kHz; dependent on sensor length, conversion time, sensor type
Connection method 2-wire
Wiring fail indication yes
Conversion time approx. 1.2 s up to 20 ms, depending on configuration and filter setting, default: approx. 125 ms
Temperature range in the range defined in each case for the sensor (default setting: type K; -200…+1370 °C); voltage measurement: ±30 mV…±75 mV
Resolution 0.1 °C per digit
Measuring error < ±0.3 % (relative to full scale value)
Electrical isolation 500 V (E-bus/signal voltage)
Current consumption power contacts
Current consumption E-bus 200 mA
Bit width in the process image 2 x 32 bit TC input, 2 x 16 bit TC output
Special features open-circuit recognition
Weight approx. 60 g
Operating/storage temperature -25…+60 °C/-40…+85 °C
Relative humidity 95 %, no condensation
Vibration/shock resistance conforms to EN 60068-2-6/EN 60068-2-27
EMC immunity/emission conforms to EN 61000-6-2/EN 61000-6-4
Protect. class/installation pos. IP 20/variable
Approvals CE, UL, Ex