Mettler Toledo IND231 Manuel D'installation page 26

2.4.6. Analog Load Cell Connection
TO AVOID DAMAGE TO THE PCB OR LOAD CELL, REMOVE POWER FROM THE IND231/IND236 TERMINAL AND WAIT
AT LEAST 30 SECONDS BEFORE CONNECTING OR DISCONNECTING ANY HARNESS.
Load cell connections are made to the load cell connector on the main board, indicated in Figure
2-16.
The IND231/236 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 this installation is
within limits, the total scale resistance (TSR) must be calculated, as follows:
Before connecting the load cells, ensure that the TSR of the load cell network to be connected to the
IND231/IND236 has a resistance greater than the minimums listed above. If the resistance is
below the minimum, the IND231/IND236 will not operate properly.
In addition, the maximum cable distance must be reviewed. Table 2-3 provides recommended
maximum cable lengths based on TSR and cable gauge.
The IND231/IND236 terminal is designed to support both 2mV/V and 3mV/V load cells from the
same circuitry. A load cell output rating selection jumper is not required.
Table 2-4 and Figure 2-23 show the terminal definitions for the analog load cell terminal strip. Note
that when using four-wire load cells, jumpers must be placed between the +Excitation and +Sense
terminals and between the −Excitation and −Sense terminals.
2-12 METTLER TOLEDO IND231/IND236 Installation Manual
TSR =
Table 2-3: Recommended Maximum Cable Lengths
24 Gauge
TSR (Ohms) (meters/feet)
350 243/800
87 (4-350 Ω cells) 60/200
Table 2-4: Load Cell Termination Pin Assignments
NOTICE
Load Cell Input Resistance (Ohms)
Number of Load Cells
20 Gauge
(meters/feet)
610/2000
182/600
Pin Signal
1 +EXC
2 +SEN
3 +SIG
4 Shield
5 -SIG
6 -SEN
7 -EXC
16 Gauge
(meters/feet)
1219/4000
304/1000
30094756 | 04 | 02/2021