GW Instek GOM-802 User Manual - Manual (Page 18)

GOM-802 DC MILLI-OHM METER
USER MANUAL
⎯ ⎯
30
Example—Calculate the resistance of a PT-100 RTD at 100℃(T). The
following R
0
(Ωat 0℃), alpha, beta, and delta values are used for the
PT-100 RTD:
T=100℃
R
0
(Ωat 0℃)=100Ω
Alpha=0.003850
Beta=0.10863
Delta=1.49990
A, B, and C are calculated according to above value as follows:
A=0.00391
B=5.77e-7
C=4.18e-12
The resistance of the RTD at 100 ℃ (R100) is then calculated as
follows:
R
100
=R
0
[1+AT=BT 2 +CT 3 (T-100)
=100{1+[(0.00391)(100)]+[(-5.77e-7)(100 2 )+[(-4.18E-12)
(100 3 )(100-100)]]
=100[1+0.391+(-0.006)+0]
=100(1.385)
=138.5Ω
(4) Temperature Sensor Terminals
Source+ Sense-
Source-
Sense+
GOM-802 DC MILLI-OHM METER
USER MANUAL
⎯ ⎯
31
8. MAINTENANCE
Qualified personnel execute the following instructions only. To avoid
electrical shock, do not perform any servicing other than the operating
instructions unless you are qualified to do so.
8-1. Line fuse replacement
If the fuse blows, the meter would not work. Try to determine and correct
the cause of the blown fuse, then replace the fuse with correct rating and
type shown as below:
FUSE RATING AND TYPE
100/120V TT0.3A 250V
220/230V T0.25A 250V
F101 on PCB T6.3A 250V
WARNING: For continued fire protection, replace only
with 250V fuse of the specified type and rating, and
disconnect the power cord before proceeding fuse
replacement.
8-2. Line voltage conversion
The primary winding of the power transformer is tapped to permit
operation from 100/120V, or 220/230V AC 50/60Hz line voltage.
Conversion from one line voltage to another is done by changing the line
voltage selector switch as shown in Figure 4-2. The rear panel identifies
the line voltage to which the unit was factory set. To convert to a
different line voltage, perform the following procedure: