Installing a 3 × 18 m weighbridge from a shipping container to a calibrated scale is six steps. Most of the work is mechanical, but the step that catches people out is the DB9 connector — a four-wire load cell does not plug into a six-wire socket without two jumpers.
Equipment in this installation
- Load cells QS-A 30 tf (or BTA 30 tf)
- Indicator XK3190-A9
- Signal-trimming junction box
- Platform 3 × 18 m in six separate modules
Step 1 — Unload and check
Lift the platform sections out of the container carefully with a crane and set the six modules down on firm, level ground. Check every accessory individually against the list — load cells, indicator, junction box, bolts, nuts, couplings — then assemble them following the reference numbers supplied.
Fit the longitudinal check rods at both ends of the platform.
Step 2 — Join the modules
Step 3 — Set the load cells
Lift the platform and place each load cell under its rocker ball, following the numbers already marked on the structure.
Keeping to the marked positions is what makes corner correction traceable later — an out-of-tolerance corner points at a known cell rather than an unknown one.
Step 4 — Cables into the junction box
Run the 8 or 10 load cell cables back to the main junction box and land each on its marked terminal.
Step 5 — Junction box to indicator
Run the signal cable from the junction box to the XK3190-A9. The load cell input is a DB9 connector:
| Pin | 1 | 2 | 5 | 6 | 7 | 8 | 9 |
| Signal | EXC− | SEN− | SHIELD | EXC+ | SEN+ | SIG− | SIG+ |
Four-wire cells need two jumpers
A four-core cable has no sense wires. Link pin 1 to pin 2 and pin 6 to pin 7 so excitation and sense are tied together at the connector — without those jumpers the indicator sees no excitation feedback and the reading will not behave.
Soldering a four-core cable into the DB9
| 1 linked to 2 | 6 linked to 7 | 5 | 8 | 9 |
| Black | Red | Shield | White | Green |
Two settings for the PC connection
The PC and remote display connect through a DB15. On the indicator, two parameters govern the link:
- bt x — baud rate, x from 0 to 4: 0 = 600, 1 = 1200, 2 = 2400, 3 = 4800, 4 = 9600
- tF x — transmission mode, x from 0 to 1: 0 = continuous, 1 = on command
Step 6 — Load test and calibration
Test with known load, correct the corners and calibrate. Once the readings hold across the platform the weighbridge is ready for service.
Where the scale will be used for trade, calibration is not the last step — legal verification follows separately.
Installation note
KALA Technical Notes
An analog weighbridge that reads erratically from the first day is usually a connector problem, not a cell problem — missing sense jumpers being the most common. Send us the indicator model and the number of cable cores you have, and we will confirm the connector wiring.
● Truck scale platforms, load cells, junction boxes and indicators.