Analog Load Cell Interface; High Precision (Idnet) Interface; Pdx ® Digital Load Cell Interface - Mettler Toledo IND780 Guia De Instalacion

The field circuit parameters associated with the IND780 terminal are underlined in the above
formulas. The other parameters are related to the other approved apparatus or the connecting cable.
If the above conditions are not true, then the circuit must be treated as an incendive input or output
and protected accordingly. If the parameters compare favorably as shown above, then no special
protection is required for the wiring. Always refer to the electrical regulations for the country of
installation for specific wiring requirements.
2.2.1.

Analog Load Cell Interface

The analog load cell connection is rated non-incendive on the IND780 terminal by both UL and
DEMKO. The field circuit parameters are listed next.
2.2.2.

High Precision (IDNet) interface

For the IDNet interface in Europe, the normal operating parameters for voltage must be compared
and the temperature must be reviewed. A power comparison and current comparison are not
required in Zone 2/22 applications. The comparison is the same as for analog load cells.
2.2.3. PDX
The PDX digital load cell connection is rated non-incendive on the IND780 terminal by UL for the US
and Canada and nonsparking (nA) by DEMKO for ATEX and IECEx installations. The field circuit
parameters are associated with power to the digital load cells, communication on the CANBus
64063214 | 07 | 02/2018
V or U (Maximum voltage permitted) ≥
max i
C (Input capacitance) + C
i
L (Input inductance) + L
i
V or U (T-Brick voltage permitted)
max i
I o I (T-brick current permitted)
max i
Note: The scale connected to the IDNet interface must also be approved for use in Zone 2/22
applications.
Electrical Parameters
IDNet Supply
IDNet current loop interface circuit
RS422 interface circuit
Digital Load Cell Interface
®
METTLER TOLEDO IND780 Division 2 and Zone 2/22 Installation Guide
V
oc
(Cable capacitance) ≤ C
cable a
(Cable inductance) ≤ L
cable a
cULus ATEX/IECEx
V = 10 VDC U = 10 VDC
oc o
I = 313 mA I = 313 mA
sc o
P = 3.13 W P = 3.13 W
o o
C = 100 µF C = 100 µF
a o
L = 1.2 mH L = 1.2 mH
a o
V or U
≥
oc
≥ It or Io (IND780 current output)
ATEX/IECEx
(connector P1-C, P1-H) Voltage max.
(connector P1-A, P1-J, P1-D, P1-F)
(connector P1-E, P1-M, P1-L, P1-K)
or U (Total voltage output)
o
or C (Allowable capacitance)
o
or L (Allowable inductance)
o
(IND780 voltage output)
o
12.4 VDC
Voltage max. 12.4 VDC
Current max. 24.8 mA
Voltage max. 5.15 VDC
2-5