Operational Example Of The 4-20 Ma Input - Burkert 8400 Manuel Utilisateur

Adjustmentandfunctionalities
T° corresponding to a 4 mA input current
Min. commutation range
1
0
Lower relay threshold (OLO)
Fig. 20: Operational diagram of the 4-20 mA input
9.3.3.

operational example of the 4-20 mA input

In the example in Fig. 21 :
- the commutation range is between 0 and 100°C
- the hysteresis is 20
- DELT is equal to hysteresis/2 so DELT = 10°C.
→
Calculating the temperature corresponding to an input current of 4 mA: Min. commutation range + DELT = 0 + 10 = 10°C
→
Calculating the temperature corresponding to an input current of 20 mA: Max. commutation range - DELT = 100 - 10 = 90°C
→
Set the transmitter parameters with the temperatures calculated (see chap.
Type 8400
external setpoint 4-20 mA
DELT DELT
DELT
Hysteresis (= 2x DELT)
T° corresponding to a 20 mA input current
Max. commutation range
DELT
Upper relay threshold (OHI)
9.7).
Relay thresholds
english
23