Objective
Monitor temperatures in refrigeration and freezing equipment in the freezing and storage processes of products resulting from the slaughter and processing of quails. With this application, it is intended to gather all registers in a single terminal to facilitate data consultations and application monitoring.
Implement a monitoring system with alerts and notifications that focus on the most determining variables in the entire process.
Solution
Sensors
Temperature measurements are performed by the transmitters that are part of the DUOS wireless solutions. The main sensor is at the end of a prove that is attached to the transmitter and inside the device there’s a second probe that simulates the product’s temperature. Although the monitoring focuses on cooling and freezing processes, the transmitters ensure efficient temperature monitoring in temperature ranges that can vary between -30C and 30C.
Repeater
A DUOS repeater was included in the solution to reinforce the range and redundancy of communications between the transmitters and the gateway. It is an indispensable equipment for the reliability of the network in more demanding applications.
Gateway
The solution gateway allows you to install up to 55 transmitters on the same network. This device ensures automatic mapping of the network and establishes communication through the channel with better connection conditions for the transmission of data packets.
Software
The software included in the solution allows uses to view and analyse the collected data. In this tool, the user configures the alarms and all available notifications methods. Each alert can be filed with an associated comment in order to justify the event. The individual export of the data and alerts of each sensor to a detailed file is available to, at any time, meet the legal requirements imposed by the competent authorities.
Technical Details
The types of final products produced have specific conservation methods. This plurality makes it necessary to have different refrigeration equipment for refrigerating and freezing products.
Monitoring includes 4 points:
- Freezing tunnel;
- Refrigerated chamber;
- Freezing chamber;
- Freezing container
Freezing tunnel
The requirement of this equipment for the transmitter is of a higher degree compared to the other measuring points. The normal operating temps of this equipment, used for deep-freezing of products, are close to -30C, which proves to be a test of the transmitter’s measuring capacity and battery performance.
This equipment is used to perform the first freezing process on products that fall into this category. After staying in the freezing tunnel, the products go to the freezing chamber. The transmitter was installed on one side of the tunnel, in the suction zone of the evaporators, as it is a more strategic point both in terms of temp and to facilitate maintenance and verification procedures.
Refrigerated chamber
The refrigeration chamber is used to store products that only need to be in a refrigerated environment. The products are placed in this space from the moment their transformation in complete until the moment they are properly identified and sent for dispatch. The operating temperatures registered in this operation are around 0C, with oscillations in the order of 2 or 3 degrees caused by opening the door, for product transit.
The fixing location of the chosen transmitter matched with a location previously used by the temperature probes associated to the control that recorded the temps, but which required the manual registration of temp values, in order to comply with legal requirements, to be carried out naturally.
Freezing chamber
The freezing chamber is one of the static storage points for the products that need to be frozen to guarantee their quality. The products go through the freezing tunnel and are stored in this space. The temperature difference between the cooling tunnel and the freezing chamber, under normal operating conditions, is 10C (in absolute). The temperature transmitter was placed on one of the walls, next to the suction zone of the cold motors. The choice of this positioning is intended to minimise the recording of misleading readings caused by the emission of cold directly on the transmitter probe, thus registering the air temp inside the chamber more accurately.
Freezing container
Attached to the building where the chambers are installed there is a movable freezing container in constant operation. This equipment is used to store frozen products pending for shipment, preventing the freezing chamber from becoming constantly overcrowded. The transmitter was placed on the end opposite to the door. In this case, the influenced of stock entry and exit through the door has a lesser impact on the registered values. Due to the distance between the transmitter and the gateway and the signal blockages created by the physical environment, a repeater was installed inside the building, with a line of sight for the container.
The repeater acts as an intermediate device that improves the network reliability, adding another crossing point that speeds up the data transmission between various elements of the network.
Hardware + Software
In the hardware side of the solution, the gateway is the end point of the data transmitted by the transmitters through wireless network. The gateway is physically connected to the terminal computer via an USB port, which will allow the PlugThings software to read the data through the Modbus RTU communication protocol. Taking into account the communication protocol, each transmitter has a dedicated Modbus RTU address which is stipulated at the time of configuration, and which is used to relate to the data received at the gateway.
Alerts
Alerts are essential to inform users whenever any of the monitored variable’s goes out of their normal range and influences the process. Since the business aspect is included in the food industry, there are rules and guidelines that define the legal requirements regarding the temp in the storage of foodstuffs. Their reference values for the customers process require that the products be stored at temps of -18C or less. Some alarms have been established to safeguard these indications and alert the user to deviations from the reference values. In addition to the process temps, were created alarms for the voltage of the transmitters’ batteries. With exposure to low temps, batteries tend to drop in voltage over time, jeopardising the temp monitoring process. The software also allows to add alarms that focus on the network signal so that the use is alerted when the signal is above or below the defined values.
Conclusion
The isolation provided by the physical environment was one of the main difficulties addressed in the smooth functioning of the entire solution. However, the signal values recorded are within those considered satisfactory, meeting the requirements of the entire application. The different temperature range of each equipment allowed to observe, locally, the variations in signal and voltage of the transmitters’ batters and to observe the behaviours that the sensors have until the solution is stable and in normal operation. The process of periodic verification of the transmitters carried out by the same entity that certifies the solution, becomes a more expeditious, reliable and comfortable task, so that the transmitters are easily removeable and taken to the verification baths. This portability avoids the need to remove wired temperature probes or having to transport the bath containers into the cold equipment, which would make the task more time consuming and expensive for the customer.
This solution brings immediate benefits to the client, which optimises the entire temperature recording process and ends up impacting its own production process:
- Reduction of resources allocated to the temperature record
- Optimisation of periodic verification
- Easy installation layout change
- Prevention of product losses
- Product quality assurance
Enter your details below to access the downloads.