HACCP-compliant Temperature Documentation and Monitoring in a Refrigerated Warehouse

According to the HACCP approach and in line with legal requirements, continuous tem-perature recording is required for refrigerated storage of food and pharmaceutical products. GesySense is a wireless temperature monitoring system that performs this task while being easy to install and virtually maintenance free.

Local conditions

The description below relates to a food wholesaler’s cold storage warehouse with six cold storage rooms. The temperature of the rooms is between 4 °C and 5 °C. The walls are normal masonry, one room has metal walls. The external dimensions are approx. 45 x 50 [m].


  • Continuous recording of the room temperatures in the cold storage rooms, the goods receiving area and the platform
  • Recording of all measurements on the opera-tional computer
  • Failsafe reliability of the recording
  • Display of the current temperatures
  • Monitoring of the temperatures with regard to adjustable limit values and warning limits
  • Alarming the responsible person if the temper-ature approaches or exceeds any of the limitsRealisierung


Measurement and wireless transmission

GesySense wireless sensor modules

6 Thermo-Sensors
2 PT1000 sensors, temperature measuremen behind the metal wall and 60 cm thick masonry.
3 repeaters, stabilization of the wireless connection

Measurement and recording

GesySense Receiver LAN,

  • Wireless reception of the measurements
  • Buffering and forwarding to a Delta 2000 data server via TCP/IP
  • Display of the current readings and temperature profiles on a local website


Delta 2000 GesySense

  • Recording and evaluation of the data with re-gard to the warning and threshold values as well as the parameters for operation of the wireless network
  • Generation of differentiated email messages when warning levels and thresholds are reached
  • Display of the current values on a local website
  • Archiving of the measured data

Alarm distribution

E-mail – SMS gateway provided by mobilant with situation-dependent distribution lists

User information and system management

Windows PC with LogIt

  • Recording and visualization of the data with warning and threshold values
  • Status information about the operation of the wireless network
  • Tamper-proof archiving
  • Print-out of temperature logs
  • Administration of the wireless network, message e-mails and configuration of wireless modules


Installation was performed with an electrician, a refrigeration specialist and the operator’s IT man-ager. A Gesytec employee was involved in an ad-visory capacity. The installation of the devices took 1 day, including commissioning of the system.

Im Betrieb

The GesySense system provides the following information when in operation:

  • Tabular and graphic visualization of the current temperature profile on the operational com-puter with display of the adjustable warning limits and thresholds
  • Messages and parameters concerning the op-erating status of the wireless network
  • Viewing of the current temperature profiles (graphic, tabular) and operating parameters from various computers on site
  • E-mail or SMS to freely definable recipients, with different people responsible if a warning or threshold is reached.
  • Tamper-proof archiving of all measurements, optionally with data reduction to the relevant measuring intervals for the required documen-tation
  • Printout of the measuring logs
  • Maintenance cycle for the Thermo-Sensors > 5 years


  • Independent monitoring system
  • Reliable documentation
  • Targeted warnings
  • Redundant data storage
  • Low installation costs
  • Transparent operating situation
  • Low-maintenance operation
  • Flexible adjustment of threshold values and alarm chains