1. Introductions and safety training
2. Planning meeting with all involved parties
3. Walk around the plant to see the layout

1. The equipment to be weighed must be free to move a few mm in order to avoid friction
   Check that there is at least 10mm gap between the weigh equipment and the surroundings
   Each connection pipe must have a flexible connection or a gap
   On small systems the flexible must be made from a thin material
   If using flexibles made from fabric then check that there is some slack in the fabric
   Each electrical cable must be flexible
   Each pneumatic or hydraulic connection pipe must be flexible
   Make sure that there is nothing in the tank
   Make sure that there is nothing loose on top of the tank
   When welding on the tank be sure to connect the earth on the tank so that there is no current flowing through the load cell. Earth straps across the load cell are also good.
   When using RLC load cells with a self aligning foot, check that the factory supplied load button is removed. If both are used the foot will not fit all the way into the load cell.

1. Do not cut the load cell cable, this will affect the calibration of the load cell
2. SSB load cell wire colors : Ex+ green ex- black signal+ white signal- red; Excitation resistance = 350ohms, signal resistance = 350ohms
3. SHB load cell wire colors : Ex+ green ex- black signal+ white signal- red; Excitation resistance = 450ohms, signal resistance = 350ohms
4. RLC load cell wire colors : Ex+ pink ex- gray signal+ brown signal- white; Excitation resistance = 1100ohms, signal resistance = 1000ohms
5. Measure the ohms for each load cell excitation and signal, do NOT use a mega, maximum 50Vdc

1. Check that the supply voltage is within 10%
2. Turn on the power to the instrument
3. Press and hold the menu button until the display changes to ----
4. If there are alarms then press the menu button to go pass
5. If there is a password then press each key from right to left
6. Enter the service menu, enter the preset menu
7. Setup the decimal point that you would like the display to read
8. Setup the zero menu to read 0
9. Setup the span menu to the total capacity of the load cells eg. 3x 5T = 15000
10. Check that you are in gross mode
11. If you are using the sense wires for the excitation then cut the two sense links on the PCB
12. Tighten all glands and fill any unused glands

1. All the load cells are wired in parallel
2. Wire the load cell screen, excitation positive and negative in the junction box
3. The excitation + is linked to the sense + in the junction box
4. The excitation - is linked to the sense - in the junction box
5. The cable from the load cell junction box to the transmitter MUST be a six wire cable to eliminate any errors on the excitation voltage
6. With the power on, measure the excitation voltage and record this value
7. Measure the mv signal from each load cell and record this
8. The mv should be in the same range unless there is a large difference in the weight of the tank from one side to the next
9. Connected the mv signal in the junction box
10. Measure the total mv going out of the junction box and record this
11. eg. 2.545mV
12. Tighten all glands

1. Put a test weight directly on top of the load cell
2. Check that the display reads the correct weight
3. Take the weight off and check that the display returns to zero
4. If the display does not return to zero then you have a friction problem, see the mechanical section
5. Repeat for each load cell

1. The reading on the display is the weight of the tank
2. Use the back balance menu to tare off the tank
3. The display should now read zero
4. The weight of the tank is stored in the SF.1 menu
5. Keep a record the SF.2 value for future

1. Total load cell output = measured excitation * specified mv/v
2. eg. 9.985V * 2 = 19.97mV
3. Take 2/3 of the load cell capacity for the test
4. eg. 3 x 5T load cells = 10 000Kg test
5. How many mV for 10 000Kg ?
6. 19.97 * 10 000 / 15 000 = 13.313mV
7. Add the weight of the tank
8. 13.313 + 2.545mv = 15.858mV
9. simulated the mv at the 6004 signal input
10. Check that the display is correct
11. If the display is not 10 000 then enter the service menu, prec UP, tare UP, span enter, 10 000 enter
12. The display will flash until a new SF.2 value has been calculated
13. The display will read 10 000
14. Record the SF.2 value

1. With the tank empty, do a back balance to tare off the tank
2. Load a known weight onto the tank, the bigger the better
3. Eg. 10 000Kg
4. Menu service, presets up, b.bal up, span enter, 10 000 enter
5. The display will flash until a new SF.2 value has been calculated
6. The display will read 10 000
7. Record the SF.2 value
8. Unload the dead weights and check that the tank returns to zero

Analogue output

1. Setup the analogue output as per the customer range
2. Note that this can be smaller that the load cell capacity
3. The out.fs menu is the display value required for the full scale output
4. Simulate mv at the input of the 6004 and check the output
5. Check the zero on the 6004 display = zero on the customer system
6. Check full scale on the display = the value on the customer system
7. If the customer system is reading a different value then change the out.fs menu to read the same
8. Check midrange on the display = the customer system
9. Keep a record of the OUT.FS value

Robert Howcroft
Pieter Deysel

Email info@instrotech.co.za