Worthington CS200, Инструкция по эксплуатации и техническому обслуживанию

Страница: 35 / 56

35
CS200
Control Systems
Controller
Operation
LED Status Wheel Flash Patterns
Temperature Thermocouple Select
The chamber temperature is monitored with 1 or 2 Type T thermocouples. The thermocouple is placed in the
chamber to monitor temperature level at the top of the inventory system. Factory installation includes one
thermocouple inside the thermocouple tube at an elevation to match the height of standard racks. A second
Type T thermocouple may be added to monitor another location inside the chamber. Both thermocouples can
be activated/deactivated through the menu system.
Temperature Calibration
The CS200 CONTROL SYSTEM uses a Type T thermocouple to measure temperature within the Cryostorage
freezer. The temperature curve for a thermocouple is nonlinear so it is important that the CS200 CONTROL
SYSTEM have a good calibration to provide accurate temperature readings. The temperature is traceable to the
National Institute of Standards and Technology (NIST) ITS-90 Thermocouple Database.
There are three important reference points needed for calibration:
• Ambient Temperature: Room Temperature
• Ice Water: 0°C
• Liquid Nitrogen (LN
2
): -196°C (-320°F)
The ambient temperature is the temperature measured inside the control box and is used to
provide temperature compensation adjustment. This is calibrated at the factory and should
not be adjusted in the field.
Ice water and LN
2
provide the reference points on the temperature curve. If these two points are
calibrated correctly then all other points (temperatures) on the curve are correct.
The accuracy of a thermocouple is +/- 1°C or +/- 1.5% of the reading, whichever is greater.
To check a calibration, dip the thermocouple in ice water and then LN
2
. If readings are within
accuracy specifications noted above, the temperature circuit on the control is properly
calibrated. If not, follow the steps below to calibrate the temperature.
Condition LED Flash Property
Normal Clockwise pattern, 1 LED per second
General Error Clockwise pattern, rapid rotation, flash
Table 7.0 LED Status Wheel Flash Patterns