GRAPHTEC GL840 - Noise Countermeasures

2-35
CHAPTER 2 Checks and Preparation
2.16 Noise Countermeasures
•
Be sure to connect the chassis GND of the measurement object.
It may become effective by ensuring that the chassis GND wire of the measurement object is connected
to a good ground.
Z3
GL840
Z1 Z2
+
-
Vin
R1
R2
Measurement object
Thermocouple Input terminals
•
Connect the signal chassis GND to the measurement device chassis ground.
Use a short, thick lead to connect the chassis GND of the measurement object to the GL840’ chassis
GND. It will become even more effective if the ground potentials are the same.
GL840
GND GND
Measurement device chassis
•
Noise countermeasures
If measured values uctuate due to extraneous noise, conduct the following countermeasures.
(Results may differ according to noise type.)
Ex 1 : Connect the GL840’s GND to ground.
Ex 2 : Connect GL840’s GND to measurement object’s GND.
Ex 3 : In the AMP settings menu, set lter to any setting other than “OFF”.
Ex 4 : Set the sampling interval which enables GL840’s digital lter.
Use the “OTHER” menu to set the commercial power frequency you use.
Refer to "3.4 Setting Menus" for details.