Mettler Toledo IND780 Guia De Instalacion página 33

talking must be evaluated. Note that the field circuit parameters for capacitance of the load cell
must be multiplied by the quantity of load cells used. The inductance value is the same for 1
through 24 load cells since the inductance is in parallel. Also note that the field circuit parameters
for the load cell cable must be multiplied by the total load cell cable length.
64063214 | 07 | 02/2018
Power evaluation
V or U must be ≥ V
max i (l/c) oc
26.4 VDC ≥ 12.6 VDC
C + C ≤ C or C
i (l/c) cable a o (PDX)
C = 11 nF * 10 cells = 110 nF = .110 µF
i (l/c)
C = 60 pF / foot * 600 feet = 36,000 pF = 0.036 µF
cable
(.110 µF + 0.036 µF) = 0.146 µF ≤ 59.4 µF
≤ L
L + L or L
i (l/c) cable a o (PDX)
L = 0 µH
i (l/c)
L = 0.2 µH / foot * 600 feet = 120 µH
cable
(0 µH + 120 µH) = 120 µH ≤ 200 µH
must be ≥ V
V or U
max i (l/c) oc
26.8 VDC ≥ 5.277 VDC
C + C ≤ C or C
i (l/c) cable a o (PDX)
C = .602 nF* 10 cells = 6.02 nF = .00602 µF
i (l/c)
C = 60 pF / foot * 600 feet = 36,000 pF = 0.036 µF
cable
(.00602 µF + 0.036 µF) = 0.04202 µF ≤ 1000 µF
≤ L
L + L or L
i (l/c) cable a o (PDX)
L = 0 µH
i (l/c)
L = 0.2 µH / foot * 600 feet = 120 µH
cable
(0 µH + 120 µH) = 120 µH ≤ 2.0 mH
CANBus listening
must be ≥ V
V or U
max i (PDX) oc
26.8 VDC ≥ 5.277 VDC
≤ C
C + C or C
i (PDX) cable a o (l/c)
C = .602 nF * 10 cells = 6.02nF = .00602 µF
i (PDX)
C = 60 pF / foot * 600 feet = 36,000 pF = 0.036 µF
cable
(.00602 µF + 0.036 µF) = 0.04202 µF ≤ 1000 µF
METTLER TOLEDO IND780 Division 2 and Zone 2/22 Installation Guide
Formula
or U
o (PDX)
Formula
CANBus talking
or U
o (PDX)
Formula
or U
o (l/c)
Pass or Fail
PASS
PASS
PASS
Pass or Fail
PASS
PASS
PASS
Pass or Fail
PASS
PASS
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