VXi VT1422A 사용자 설명서

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Field Wiring   45
Terminal Module
Considerations for
TC Measurements
The isothermal characteristics of the VT1422A Terminal Module are crucial for 
good TC readings and can be affected by any of the following factors:
1. The clear plastic cover must be on the Terminal Module.
2. The thin white mylar thermal barrier must be inserted over the Terminal 
Module connector. This prevents airflow from the VT1422A A/D Module 
into the Terminal Module.
3. The Terminal Module must also be in a fairly stable temperature environment 
and it is best to minimize the temperature gradient between the VT1422A 
module and the Terminal Module.
4. The VXI mainframe cooling fan filters must be clean and there should be as 
much clear space in front of the fan intakes as possible.
5. Recirculating warm air inside a closed rack cabinet can cause a problem if 
the Terminal Module is suspended into ambient air that is significantly 
warmer or cooler. If the mainframe recess is mounted in a rack with both 
front and rear doors, closing both doors helps keep the entire VT1422A at a 
uniform temperature. If there is no front door, try opening the back door.
6. VXI Technology recommends that the cooling fan switch on the back of the 
of the CT-400 Mainframe be in the "High" position. The normal variable 
speed cooling fan control can make the internal VT1422A module 
temperature cycle up and down, which affects the amplifiers with these 
microvolt-level signals.