Closing The Enclosure; Analog Load Cell Connection - Mettler Toledo IND256 Série Guide D'installation

2.4.1.2. cFMus
2.4.1.2.1. Connection of EB per ANSI/NFPA 70, Article 504, and ANSI/IA RP 12.06.01 or Canadian Electric Code C22.2
It must be ensured that the housings of all devices are connected to the same potential via the EB
terminals. No circulating current may flow via the shielding of the intrinsically safe cables.
2.5.

Closing the Enclosure

To ensure that the front cover is correctly installed:
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2.6.

Analog Load Cell Connection

Analog cells are connected to the mainboard at the connector show in Chapter 1, Introduction.
The IND256x terminal is designed to power up to four 350-ohm load cells (or a minimum
resistance of approximately 87 ohms). To confirm that the load cell load for the installation is
within limits, the total scale resistance (TSR) must be calculated.
To calculate TSR:
Ensure that the TSR of the load cell network to be connected to the IND256x has a resistance
greater than 87 ohms before connecting the load cells. If the resistance is less than 87 ohms, the
IND256x will not operate properly.
In addition, the maximum cable distance must be reviewed. Table 2-5 provides recommended
maximum cable lengths based on cable gauge and correct operation of the terminal. Note that the
entity values for the load cell cable must be considered as a safety factor in the installation.
Figure 2-9 shows the wiring for analog load cells. When a four-conductor cell is used, +Exc must
be jumpered to +Sen and -Exc jumpered to -Sen.
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Place the front cover on a flat surface
Ensure that the seal ring is accurately located
Install the rear cover and ensure it is accurately positioned
Install the screws in their original positions
Tighten each screw to 3.0 Nm
TSR =
Table 2-5: Maximum Recommended Cable Lengths
TSR (Ohms)
One to four-350 Ω cells
METTLER TOLEDO IND256x Weighing Terminal Installation Manual
Load Cell Input Resistance (Ωhms)
Number of cells
24 Gauge 20 Gauge
(meters/feet) (meters/feet)
60/200 182/600
16 Gauge
(meters/feet)
304/1000
2-7