Weight measurement using load cell and process indicator
The indicator that you have has a 0-10V input (or 0-20mA as alternative, but it's easier to work with voltages as the specs of the load cell are for voltages).
The load cell is simply a resistive load (a Wheatstone bridge, to be exact), and requires to be excited with 10-12V (so we can work with these supplies easily). The problem is that load cells use strain gauges, which are resistances which value change with deformation, so the change in their value respect to the nominal value is small: they give a strong common mode signal.
What you need is an amplification circuit that:

Removes the common mode signal, giving 0V for 0 kg

Amplifies the useful signal, such as for 200kg you have a ~10V output


These characteristics (the first for sure) are met by Instrumentation Amplifiers (InAmps), like the AD620. To eventually increase gain (and eventually filtering some noise) you may use a multi-stage amplifier, using an OP-AMP active filter to remove some noise and split the gain between the two circuits.
Probably for load cells there are industrial amplifiers, embedding all these things in one rough box, but that goes out of my knowledge.
Update
As I was thinking, there are such things, like this guy, which gives an 1VDC (a bit small for your output, usable but you lose a digit of accuracy) or 20mA full scale output; the latter is the best for your requirements, as I think that the output in current improves noise robustness.