Fema M Series, User Manual, Page: 26 / 36

FEMA ELECTRÓNICA . SERIES M . M60-LC
26
1.16 Practical cases
Case for 4 load cells connected to a ‘junction box’. It is as -
sumed that the ‘junction box’ is used as a simple ‘connec -
tions box’. All 4 load cells are the same type of load cell,
with nominal weight of 100 Kg and 2 mV/V sensibility.
• Connect the 4 load cells to the ‘junction box’. Connect
the instrument to the ‘junction box’ using 4 or 6 wires, as
indicated in the ‘junction box’ documentation. If 4 wires
‘junction box’ is used, see section
1.8.1
to connect the
‘sense’ wires not used (‘sense’ wires must connected).
• Configure the ‘theoretical configuration of the load
cell’
(see section 1.12.2)
. Take note that the sensitivity
of the system remains the same (2 mV/V) and the nomi -
nal weight of the system is the addition of the nominal
weight of each cell (4 x 100 Kg = 400 Kg)
• Apply the ‘empirical configuration of the load cell’
(see section 1.12.2) .
• Configure the ‘system zero’
(see section 1.12.2) .
Depending on the specifications of your load cell, you
may need to apply a ‘tare’ each time that the weight is
removed from the load cell. See at section
1.11
the differ -
ent options available to activate the ‘tare’ function..
A ‘junction box’ for load cells has internal elec -
tronics that can modify the ‘signal / weight’ re -
lation provided to the instrument. Check the
manufacturer documentation of the junction box.
!
Case for 1 load cell, powered from the instrument, with
power 10 Vdc, nominal weight 100 Kg and 2 mV/V sensi -
bility.
• Connect the load cell to the instrument
(see section 1.8) .
• Configure the ‘theoretical configuration of the load
cell’
(see section 1.12.2) .
• Apply the ‘empirical configuration of the load cell’
(see section 1.12.2) .
• Configure the ‘system zero’
(see section 1.12.2) .
Depending on the specifications of your load cell, you
may need to apply a ‘tare’ each time that the weight is
removed from the load cell. See at section
1.11
the differ -
ent options available to activate the ‘tare’ function.
Case for 1 load cell, with external power.
• Connect the load cell normally, and do not connect
‘Vexc+’. Connect ‘Sense+’ and ‘Sense-’ to the load cell.
‘Vexc-’ must be connected to ‘Sense-’. See
Figure 9 .
• Configure the ‘theoretical configuration of the load
cell’
(see section 1.12.2) .
The value assigned to Vexc
does not affect the measure.
• Apply the ‘empirical configuration of the load cell’
(see section 1.12.2) .
• Configure the ‘system zero’
(see section 1.12.2) .
Depending on the specifications of your load cell, you
may need to apply a ‘tare’ each time that the weight is
removed from the load cell. See at section
1.11
the differ -
ent options available to activate the ‘tare’ function.
1 2 3 4 5 6 7
Vexc+
Signal-
Sense-
Vexc-
Sense+
Vexc+
external
Figure 9 - Connections for external power
1.16.1 Normal case
1.16.2 Load cell with external power
1.16.3 Connections with a junction box
1 2 3 4 5 6 7
Junction box
(connections box)
Figure 10 - Example for 4 load cells connection through a
‘junction box’ or ‘connections box’.