GRAPHTEC GL840 - Page 58

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CHAPTER 2 Checks and Preparation
When using the Withstand high-voltage high-precision terminal (GL840-WV and B-565)
•
Maximum input voltage
If a voltage exceeding the specied value is input, the semiconductor relay in the input section will be
damaged. Never input a voltage exceeding the specied value even for a moment.
* This applies to all the channels even if channel extension is used.
< Between +/– terminals (A) >
• Maximum input voltage : 60Vp-p (Range of 20mV to 2V)
110Vp-p (Range of 5V to 100V)
<Between input terminal/input terminal (B) >
Maximum input voltage : 600Vp-p
Withstand voltage : 600Vp-p
<Between input terminal/GND (C) >
Maximum input voltage : 300Vp-p
Withstand voltage : 2300VACrms/1 minute
+
-
+
-
+
-
C
B
GND
+
-
+
-
+
-
B
B
C
C
A
GND
[ Temperature measuring ][ Voltage measuring ]
Thermocouple
Thermocouple
Thermocouple
•
Input Circuit Diagram for Analog Input (Voltage, Thermocouples)
50Ω
50Ω
500kΩ
500kΩ
0.05μF
0.05μF
+
-
Capacitors have been incorporated into the input circuit to increase the noise elimination capability.
After voltage measurement, when the inputs have been disconnected, there will still be some electric
charge remaining.
Before starting another measurement operation, short-circuit the + and - terminals to enable self-
discharge.
The GL840 has a scan system.
While in the status (open) in which signals are not input to the input terminal, measured results may be
inuenced by signals from other channels.In such a case, turn OFF the input setting or short circuit +/-.
If signals are input correctly, measured results are not inuenced by other channels.