Sending Mettler Toledo weighing scale data over LoRa

About the Customer:

Measurements is an integral part of process plants and weighing scale are found in almost all (if not all) process plants. Mettler Toledo is the largest provider of weighing instruments for use in laboratory, industrial, and food retailing applications known for their high accuracy products that are value for money. Today, we are covering a recent application that we have collaborated with in Singapore.

The challenge:

In this particular use case, the customer is interested to send weighing data without any trunking over a long distance (2km) due to trunking costs. They will like to be able to send data via wireless directly to their SCADA in a reliable manner. The customer is particularly concerned about the signal reliability and speed of transmission as they are aware of the limitations of LoRA.

Our proof of concept:

The PoC topology is as follow:

LoRA Topo.png

During the proof of concept, we were able to pre-program a set of LoRA Terminals and tested using 2 laptops and hyper Terminal. After which, we were able to hook up to the MT Toledo by ensuring that the polarity is correct for the serial transmission to take place. (Garbage values will appear if the cabling is wrong).

Once everything is in place, we were able to see the data flowing correctly. The greatest challenge we had in the proof of concept was the buffered data. Our data is coming in after a couple of seconds and slower that what we saw on the scale. This is because the weighing scale was sending the values very quickly and the terminal unit have a buffer of 20 seconds. This is resolved after clarifications indicated that they dont need to have all the value and we removed the buffer on the device to reflect data on best effort.

All in all, our set up was fast and a total of less than 5 minutes. In conclusion, our solution using LoRA, we were able to successfully transmit data tirelessly and replaced the need for trunking of a weighing scale. Here’s a nice picture of our poc: