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By stefanini
#203312
I am new to Openscale and Loadcells .. pardon me on my question.

I am getting readings such as 156462,-59.69,lbs,19.37,0, when I have connected Openscale and one load cell. Opensclae is connected to Raspebrry pi via USB, and I am seeing this reading.

I am not able to decipher this data payload. Please help me understanding this reading what each represents.

Second question is - if I need to connect 4 load cells, will all that go into the same connection and how the readings come out
User avatar
By TS-Chris
#203316
Hello, and thanks for posting your question in the forums!
I am getting readings such as 156462,-59.69,lbs,19.37,0, when I have connected Openscale and one load cell.
OK, let me decode that for you. By default not every field is turned on and the format you're seeing is the default. The format when every field is turned on is:
timestamp , calibrated_reading , units , raw_reading , local_temperature , remote_temperature

In your case, you have the timestamp, calibrated reading, units set to lbs, local temp and remote temperature turned on.

156462
This is a time stamp that indicates the time in ms since the OpenScale was powered on

-59.69

This is the calibrated reading in pounds or kilograms.

lbs
You can change this field to say lbs if you've calibrated the device in pounds, or kgs if you've calibrated the device in kilograms

19.37

This is the local temperature of the OpenScale board.

0

This is the reading from an optional DS18B20 temperature sensor that you can attache to the OpenScale board. In your case it looks like you don't have a sensor attached and so the board is give you a 0 reading.

You can actually turn on and off some of the data fields if you wish. The following fields can be turned off.
  • timestamp
  • raw_reading
  • local_temperature
  • remote_temperature
Turning these of just make them not print. For example, if you turned all of them off, you'd only see the following output:
-59.69,lbs,

There's a menu you can access to change various settings in the OpenScale and turn the various fields on and off. Sending the letter x will get you into that menu and the menu options should be fairly straight forward in what they do.

You might also want to check out the Hookup Guide for the OpenScale. That should clear up any other questions you have about the operation of the board.
if I need to connect 4 load cells, will all that go into the same connection and how the readings come out
As to connecting load cells, you can connect 1 four wire load cell to the screw terminals on the board. We have pads on the side of the board for connecting 4 three wire load sensors. If you're connecting load sensors, you must connect all four and the wiring is as follows:
  • - = black
  • + = white
  • C = red
It is possible to connect more than one four wire load cell to the board, but you need a summing box to do that. Unfortunately we don't carry summing boxes, but a google search should turn up some options for you. We have had customers connect their load cells in parallel without a summing box successfully, but we've not tested this configuration and can't say for sure if it's accurate. Connecting more than one load cell or load sensor won't change the output, you still receive a single weight for the combination of all the sensors.
User avatar
By stefanini
#203319
You indicated on connecting 4 load cells ... "Connecting more than one load cell or load sensor won't change the output, you still receive a single weight for the combination of all the sensors."

Does that mean, there is no need to do this and can be accomplished by just using one load cell, say placed in the center of a shelf rack for example and it will be an accurate reading?

Also, you indicated that there are pads on the side of the board connecting .. what are UL/LL and UR/RR ... do I connect there and does it need a combinator?