Load Cell for Siemens PLC interface

[nonuke]

I always use summing boxes if more than one cell

 

[JesperMP]

I wrongly referenced that I liked the JOLLYTLB.
I meant the JOLLYTLS, the one with 4 dedicated inputs.
I am glad that you pointed me to it, if only by accidence

 

[Clay B.]

For the following reasons:

Dumb summing boxes has no local display. A local display is invaluable in setting up and troubleshooting.

Parallel connected loadcells may generate a plausible output signal, even if one loadcell is wonly. With dedicated inputs an alarm can be automatically generated if one loadcell is bad.

If one parallelly connected loadcell is bad, to find out which one you typically have to disconnect and reconnect the parallel loadcells and see how the signals react.

The summing box itself is an extra hassle.

See your point. We use the Dumb LOad Cell boxes and they work exactly as you describe. I am just so used to them the only thing that ever bothers me is when i have to trim the corners when I am calibrating. We also use a 4 load cell array almost all of the time.

 

[ming0521]

thanks for all of the suggestions!
God bless you all! =))

 

[JesperMP]

Pardon me for asking nonuke so directly.

But I really would like to know how the Laumas unit worked out for you.
I am guessing that by now you have put the Laumas unit into operation.
Did it work OK ?
Was it easy to setup ?

edit: I cannot find any manuals on Laumas website. Do you have one ?
I would like to give it a quick readthrough.

 

[nonuke]

Hi Jesper,
The Laumas unit works great. Its easy to setup and to do the callibration. I also used an output from the PLC as an Input to the unit to Zero it. I have a pdf file but it is 800k. If you send me your email, I will email it to you. You are correct - The pdf file isn't in the net.

 

[JesperMP]

Here is some feedback after I finally have had my hands on a Laumas TLS unit.

The manual is not very good (that is my opinion). Not as bad as I have seen, but far from being good.
Fortunately there are not that many parameters to mess with, so I quickly managed to find the right parameters and set it up.
The unit itself is as one will expect when one knows it is a printed circuit board repackaged somewhat into a DIN-rail mountable unit.
The unit is quite low-cost so we are sort-of satisfied with what we get.

I am a bit disappointed about its functionality though.
There are 4 terminal positions to connect load cells. Each position can connect a single load-cell, or op to 4 via an external summing box (for 16 in total).
The disappointing bit is that these 4 positions for attaching load cells do not mean there are 4 separate channels. It seems that there is simply an integrated summing box under the skin. I would have liked (expected actually) that I could get error signals for each channel, and that I could monitor each channel individually on the display. That would have been great for troubleshooting.
As the manual explains, if a load-cell is bad, you have to disconnect them all and start hunting the error with a meter.

So all in all, it works OK and the price is fine for what you get. But I would have liked to pay a bit more to get a bit more.