There are different ways that you can get production signals from your machines to monitor production and OEE. The method to use mainly depends on what production process you have.
Before you continue, make sure you have read our article on “How to choose what production signal to monitor?”
Different ways to get production signals
When using Evocon to get production signals and data, then there are four main ways. The first and most popular way is to either use an existing industrial sensor or to install a new one. The second option is a connection with machine PLC via a relay. And the final options are Andon lights and HTTPS requests.
Each one has its pros and cons. And you should make the final decision depending on your specific needs, which we can help figure out.
Choosing between an existing industrial sensor and a new one
Using an existing sensor is in most cases the best method to get production signals. But sometimes it is easier and more efficient to install a new one. Below you will find arguments for both sides.
- The main reason to choose an existing sensor is that the manufacturer of your machines has the best knowledge of what industrial sensor to use. Thus, providing you with the highest reliability of signal quality. It becomes critical when, for example, you have products with impure or highly reflective surfaces.
- The second aspect is the location of the sensor. Usually, existing sensors are located on the production line or in the machine so that no external factors can compromise the signals. For example, someone unintentionally touches the sensor that results in false signals.
- Using a relay connected parallel to an existing sensor output would also be a cheaper solution than getting a new one. A competent technician or electrician should have no problem finding the right wire and connecting the signal.
- Furthermore, in the case an existing sensor breaks, it is easier, less time consuming and cheaper for you. Because most probably the machine maintenance company will come and fix it.
- The main downside of using an existing sensor is that you need to involve an electrician in the process. And if you have a new production machine, then depending on the contract you might be required to order a technician from the machine maintenance company to come and take a signal from the sensor.
- Going with a new sensor is the easiest solution for you if you can find a good location for it. It should be a place where the gap between the products is at least 5 cm. And it is possible to register the signal with a regular sensor that reads signals from a reflecting surface (milk cartons, wooden details, cups, boxes, bags etc.).
Creating a connection using machine PLC
In some industries, like metal and wood processing, it is a common approach to use machine PLC to get production signals. But first, make sure you have a competent electrician on your team or a maintenance service provider.
Then you should ask if it is possible to generate a reliable signal using machine PLC – one that corresponds to what you want to measure.
Let’s take an example of a sawmill. At one of our users, an electrician configured two separate output signals to use Evocon. The first signal is “log in front of a sensor” and the second is an encoder connected to the log conveyor. They have connected both inputs to our device to calculate the length of logs that passed. In this scenario, our system only registers production if the first signal is active – i.e. there is a log on the conveyor.
The above is an excellent example, how you can utilise reliable signals from the PLC if you know what to look. And you can implement control signals to make sure that you get accurate data about your production.
The downside of using a PLC is that if it goes wrong (dies), the replacement would also need the custom program. Also, if the programming of a PLC output is bought in from a service company, then it might be costly. What is more, some companies and providers are reluctant to connect external hardware to their machines.
However, once we introduce them how Evocon works and give them more details (e.g. we use relays to isolate the connection), most are ready to help.
Andon lights are controlled (switched on and off) by PLC outputs. Each of the lights (usually red, yellow and green) has their meaning. Usually, the green light means the cycle of the machine is running. And we can interpret this signal to match what you are looking to measure in your production process.
For example, we can measure how long one cycle is. Or we can count the number of cycles (by registering when the light goes off). Also, it does not matter if the light stays on or blinks during the cycle. We can use both.
The advantages and disadvantages of using Andon lights are mostly the same as in the previous section.
HTTPS requests (hardware-free solution)
A lot of the newer production machines are already collecting data on production events. Which greatly simplifies how you can get Evocon up and running in your factory.
If your production machines register timestamps of different events to a database and the computer that holds the database can make HTTPS requests to the internet, then you can set up Evocon without using any hardware. All you need is a small program that checks the database once a minute. New information about production events is sent to our server and this data is then visualised for you to see on the shop floor or anywhere you need access.
Using HTTPS requests is the easiest solution to manage and set up, and it is also more error-proof. Because when the program is closed and later opened, then all occurred events between that time are sent to Evocon. And as stated above, you don’t need any hardware to get Evocon up and running.
We have example scripts that we can modify for different structures or types of databases. Usually, we can create the query that reads the data from your database in a short time.
If your machine has a PLC that is able to send HTTPS requests of the required format, our script isn’t needed.
What are the main things to consider?
- Do you have an electrician or a maintenance provider who understands how to get production signals and knows which are reliable?
- Is it easy to get production signals or difficult? E.g. does it involve just connecting a relay or would you have to solder an extra wire on a PCB (printed circuit board)?
- Is your machine recording production data to the database?
- Does your machine have a valid maintenance contract or is it under warranty?
If you need any help deciding what method to use, then contact our team, and we will be more than happy to help you. Just let us know what machine you are using and what production data you need.