Flintec KAL-4 - Manual (Page 4)

Digital Junction Box Type KAL-4 – Technical Manual, Rev. 1.00 Dezember 2010
Page 4 of 4
O UTPUT C ABLE C ONNECTION
Figure 2: Power supply and connection to external electronics
Depending on cable routing and the LDU’s communication settings the connection cable between junction box
and external electronics will be executed as shielded 4 wires, shielded 6 wires or separate cables for power
supply and bus communication (see also technical manual of corresponding LDU amplifier).
C ORNER C ORRECTION AT S CALES WITH F LINTEC L OAD C ELLS
Flintec load cells are manufactured with rather tight tolerances, so in most cases an additional corner
correction is not required. The best conditions are achieved if you use load cells of the same class
(Designation is done with capital letters A to I on the load cell package besides the type label).
Hint: Corner errors can have a mechanical background, e.g. sloped mounting surface of the load cell.
Procedure:
1. The 0 Ohm jumpers instead of the correction resistors must be in place (shipment status).
2. Get the display value for each corner. Use the highest possible display resolution (e.g. factor 10 or higher)
or, if this is not possible, measure the the digital weight increment using corresponding weights.
3. The corner with the lowest display value is the starting point for the corner correction. The differences of
the other corners are calculated with reference to this “basic corner”.
4. Calculate the correction resistance as follows:
Deviation in [kg]
Correction resistance [
] =
Test load in [kg]
X Input resistance of the load cell [
] *
* 1100
 input resistance for: BK2, SB4, SB5, SB6, SB14, SLB, ZLB, UB1, UB5, UB6, PB, RC3
400
 input resistance for:
RC1, SB2
Example 1: 1100
 load cell
0.1 kg corner error with 500 kg test load
0.1 kg
500 kg
x 1100
 =
0.22

Example 2: 400
 load cell
10 kg corner error with 5000 kg test load
10 kg
5000 kg
x 400
 =
0.8

5. Install the correction resistor into the junction box instead of the 0 Ohm jumper for the corresponding load
cell excitation.
6. Check the corners again. If required repeat the procedure.
Hint: 50 ppm resistors for corner correction are available as a set of 14 values from 0.22
 to 4.7  (10 pcs.
for each value; article no. 5200-030).
In the junction box you can also find a dry tablet in a plastic bag. Open the bag and leave the tablet in the
junction box. This will absorb moisture up to a certain degree. Check the cover sealing and install the cover of
the box.
Connector for LDU power supply
(LDU requires 12...24 V DC at 60 mA max. current) RS422/RS485 connector
(full-duplex or half-duplex)
12 V 0 V Shield