Connecting Thermocouples - YOKOGAWA DL850E User Manual

3.8

Connecting Thermocouples

Connecting Thermocouples
If you are connecting the compensation lead of the thermocouple to the input terminal (binding post
terminal) of the 701261 (UNIVERSAL), 701262 (UNIVERSAL (AAF)), or 701265 (TEMP/HPV), loosen
the terminal knob, pass the lead through the terminal, and tighten the knob.
If over-range is indicated, the DL850E/DL850EV may be receiving a voltage higher than the
observed waveform or measured waveform values. To prevent electric shock, check the input
voltage level.
• The 701261 (UNIVERSAL), 701262 (UNIVERSAL (AAF)), or 701265 (TEMP/HPV) is
isolated from the DL850E/DL850EV. However, applying a voltage exceeding the value
below may damage the input section. If the frequency is above 1 kHz, damage may occur
even when the voltage is below this value.
Maximum input voltage (across the input terminals, H and L, at a frequency of 1 kHz or less)
Maximum allowable common mode voltage (across the input terminal L and earth at a
frequency of 1 kHz or less)
• Correct measurements cannot be obtained when the positive and negative thermocouple
leads are connected in reverse.
• Immediately after connecting the thermocouple, the heat balance may be disturbed at
the input terminal section and may cause measurement errors. Therefore, wait about ten
minutes before making a measurement.
• In an environment where the air from the air conditioning is directly applied to the input
terminals or where there are effects from a heat source, the heat balance may be disturbed
at the input terminal section and cause measurement errors.
When making measurements in this type of environment, take preventive measures such
as changing the position.
3-34
Extension wires
(or bare thermocouple wires)
To the thermocouple
Over-range indication
Indicates the number of the channel that over-range is occurring on.
Channel indication when over-range is occurring on multiple channels
Indicates the smallest number among the channels that over-range is
occurring on.
42 V (DC + ACpeak)
42 V (DC + ACpeak) (CAT II, 30 Vrms)
Positive lead
H
L
Negative lead
WARNING
CAUTION
IM DL850E-03EN