Electrical connection Waterpilot FMX21
26 Endress+Hauser
6.5 Current consumption
6.5.1 FMX21 + Pt100 (optional)
• Max. current consumption: ≤ 23 mA
Min. current consumption: ≥ 3.6 mA
• Pt100: ≤ 0.6 mA
6.5.2 TMT182 temperature head transmitter (optional)
• Max. current consumption: ≤ 23 mA
• Min. current consumption: ≥ 3.5 mA
• Pt100 via temperature head transmitter: ≤ 0.6 mA
6.6 Maximum load
The maximum load resistance depends on the supply voltage (U) and must be determined
individually for each current loop, see formula and diagrams for FMX21 and temperature
head transmitter.
The total resistance resulting from the resistances of the connected devices, the
connecting cable and, where applicable, the resistance of the extension cable may not
exceed the load resistance value.
R
Lmax
– 2 0.09•
• L – R
U – 10.5 V
23 mA
W
m
£
413
630
195
1065
35
20
25
10.5
15
847
30
R
[ ]W
U
[ ]
V
– R
U – 11.5 V
0.023 A
£
R
Lmax
370
587
152
1022
35
20
25
11.5
15
804
30
R
[ ]W
U
[ ]
V
A B
add add
A0026500-EN
A FMX21 load chart for estimating the load resistance. Additional resistances, such as the resistance of the
extension cable, have to be subtracted from the value calculated as shown in the equation.
B Load diagram for TMT182 temperature head transmitter for estimating the load resistance. Additional
resistances must be subtracted from the value calculated as shown in the equation
R
Lmax
Max. load resistance [Ω]
R
add
Additional resistances, such as resistance of the evaluation unit and/or display unit, cable resistance [Ω]
U Supply voltage [V]
L Basic length of extension cable [m] (cable resistance per wire 0.09 Ω/m)
• When using the measuring device in a hazardous area, the relevant national
standards and regulations as well as the Safety Instructions or installation or control
drawings (XA) must be adhered to.
• When operating via a handheld terminal or via a PC with an operating program, a
minimum communication resistance of 250 Ω must be taken into account.
To Next Page
Loading...
