Fixtures & Adapters

A compression load cell is designed to be loaded along one axis. Everything about its accuracy specification assumes that, and a load arriving at an angle violates the assumption quietly rather than obviously.

When force arrives off axis, only the component along the load cell's axis is measured. The rest becomes a side load, which the load cell largely rejects, so the reading comes out low. It is also usually repeatable, because the misalignment does not change between weighings, which is exactly what makes it so hard to spot: a repeatable low reading looks like a scale that needs calibrating, and calibrating it simply bakes the error in.

The load button exists to remove that failure mode. It is a radiused dome that threads into the centreline of the DBSL on an M16 x 1.5 thread, and the curvature is the whole point: a dome contacts whatever presses on it at a single point on its own centreline, so the force is directed down the loading axis regardless of small angular misalignment in the fixture above it.

That makes a load button the right answer whenever the loading fixture cannot be guaranteed square, which in practice is most fabricated test rigs and most field installations. On a machined, dowelled, laboratory-grade fixture it matters less. In a workshop it matters a lot.

The three load buttons are the same idea scaled, and the scaling is not cosmetic.

1t to 5t at $30, 10t and 20t at $45, and 30t at $80. The price roughly triples across the range because the button has to carry the load cell's full rated capacity through a single contact point, and the contact stress at that point is what sets the size and the material.

The rule is to match the band to the load cell's capacity, not to the load you expect to apply. A load cell is routinely used well below its rating, and it is tempting to reason that a 30t load cell being used at 4t only needs the small button. That reasoning fails the moment somebody overloads the rig, and it fails at the button, which is the part in direct contact with the load.

There is also a practical reason: the button is a consumable in a way the load cell is not. A dome that has been hammered, dented or brinelled by repeated point loading no longer contacts cleanly, and a flattened dome reintroduces exactly the alignment error it was fitted to remove. Inspecting the button is a sensible part of periodic calibration, and replacing one is a small fraction of the cost of the load cell.

A DBSL is a compression load cell: force pushes into it. A great many test applications need to pull as well, and buying a second load cell for that is the expensive answer.

The tension base at $150 is the cheaper one. The load cell mounts to it through the bolt circle around its own circumference, and the base then presents a central M24 x 1.5 threaded hole. With the load cell captured that way, the assembly can be fixtured from the base and loaded in both tension and compression.

The part worth reading twice is Transcell's own claim about it, because it is not the obvious one. Because the base is machined to very tight tolerances to complement the DBSL, fitting it typically improves measurement quality in both loading modes, not just in tension. The base gives the load cell a flat, square, dimensionally controlled reaction surface, which is precisely what a load cell's specification assumes and what a fabricated bracket rarely provides.

So the tension base is worth considering even on a compression-only rig where repeatability matters more than the cost of the fixture. It is listed for the 1t to 5t capacity band. Bases for the 10t to 20t DBSL (part 3112240007) and the 30t DBSL (part 3112240009) have drawings on the DBSL product page but are not in the online shop, so ask us about one.

The load cell simulator at $130 has nothing to do with the other four parts, and it belongs in every service kit.

When a scale reads wrongly, the fault is somewhere in a chain: the load cell, the cable, the junction box, or the instrument. Testing that chain by substitution normally means dismantling the scale, which is slow and, on a sealed installation, disruptive.

A simulator short-circuits the process. It presents the instrument with a known, stable bridge signal in place of the real load cell. If the instrument reads that signal correctly, the instrument is good and the fault is downstream in the load cell, the cable or the box. If the instrument reads the simulator wrongly, you have found the fault without touching the mechanics at all.

That single test removes roughly half the possibility space in a couple of minutes, and it does it at the indicator rather than under the platform. Ours ships with its cable, which matters more than it sounds: a simulator you cannot connect to the instrument in front of you is not a diagnostic.

It is also the right tool when commissioning: proving the instrument and the wiring before the mechanics are finished lets two jobs happen in parallel. Its full-scale output is 1.8 mV/V ±10%, on a 6-wire lead with sense wires, so it suits 4-wire and 6-wire inputs alike.

All four mechanical parts here are specific to the DBSL, which is a pancake load cell. The M16 x 1.5 centreline thread and the circumferential bolt circle are DBSL dimensions, so none of them adapts to another family.

The principle, though, is general. Any compression load cell benefits from a load introduced down its axis, and any load cell benefits from a flat, square reaction surface. What changes between families is the thread and the mounting pattern, not the physics.

For other Transcell families, the equivalent hardware is usually part of the mounting arrangement rather than a separate catalog item: S-beam load cells take rod ends and clevises, and beam load cells take mounting kits that set the load path. If you are building a rig around a load cell that has no listed fixture, tell us the family, the capacity and the direction of loading and we will machine what it needs.

And if the load cell is in a platform rather than a rig, the equivalent question is answered by feet: alignment at the floor rather than at the load cell, the same idea one step further out.