- #1

Claudio_Baldo

- 14

- 0

I am starting the re-design of the PLC software for a preexisting Truck Crane Loader.

I will receive the Weight Chart to see what the limits are and I was wondering how to exactly calculate the resulting weight on the Crane.

The CRANE is already on place, it has two joints and a telescopic extension.

We want to change the primitive control system to a more advanced one, this is to say, adding some safety features (software through a PLC).

We will add a load cell in order to measure the weight which has being lifted, two inclinometers in order to measure the angles of the two joints and one encoder to measure the opening of the telescopic extension.

My questions (at the moment) are two:

the first is if for the calculation of the moment of the force I can take the static force weight (measured by a load cell) and the distance from the pivot (so convert the angles of the two joints and the telescopic for the horizontal vector component).

I am pretty sure about this but I need to confirm it...

The second is how I can calculate the force when moving the CRANE and if this is already taken into account in the weight chart.

In specific the inertia will increase depending on the acceleration/deceleration of the movement, so I guess I need to program some sort of soft start/soft stop function in order to limit these values.

Also, are there any other forces I should take into account when designing the software?

The idea is to limit the operation depending on the weight.

i.e. With a max weight of 500kg at 2m from the pivot (weight chart), if the CRANE is loaded with this 500kg and extending the telescopic extension from over 1m, once the extension gets to 2m, the manual command is stopped and an error is showed to the operator.

The setup will be interlocked with the legs pressure and will vary when they are fully extended.

We will use a limit below the max weight of the chart, so this should be an additional safety, but with the software we want to avoid any type of tip over/damages/accident. This will include the break of metal ropes etc...

Many thanks to everyone able to help!