Environmental chamber control unit

A control unit for adding to an environmental chamber, the chamber comprising:

• a thermostat-humidistat container configured to define a closed space;
• an air conditioner configured to control temperature and humidity in the thermostat-humidistat container;
• a first temperature and humidity sensor configured to measure the temperature and the humidity inside the thermostat-humidistat container;
• and
• a controller having predetermined set values for temperature and humidity, and configured to receive a first signal from the first temperature and humidity sensor and to control the air conditioner based on the first signal and the predetermined set values;
• wherein
• the control unit includes:
• a second temperature and humidity sensor placed in different location with the first temperature and humidity sensor inside the thermostat-humidistat container, and configured to measure temperature and humidity inside the thermostat-humidistat container;
• and
• an additional unit configured to receive the first signal and the predetermined set values from the controller, and a second signal from the second temperature and humidity sensor, and to compute a correction value based on the received first and second signals, and the received predetermined setting values, and to send the correction value to the controller.