Simex SRT-L70, User Manual

Page: 10 / 36

User manual - METER SRT-L70
or 3-wire circuit (Figure 4.5b). Due to precision of measurement 4-wire circuit is
recommended.
If 2 wire circuit is used it is recommended to connect sensor accordingly to Figure
4.5c
. In this case, the resistance of wires should be as small as possible, to avoid of
measurement errors. Measured value can be corrected (constant correction) using
„
toFS ” parameter from menu „ inPt ”. Due to low precision 2-wire connection is not
recommended.
When 4-wires or 2-wires connection is used, the resistance of particular wires (Ra ÷ Rd)
CAN BE DIFFERENT
. When 3-wires connection is used, the resistance of particular wires
(Ra ÷ Rd)
MUST BE IDENTICAL
to enable proper compensation of it's resistance. The
resistance of particular wire should not be greater than 20
Ω
.
a) b) c)
Figure 4.5. Connection of sensors:
a) 4-wires circuit; b) 3-wires circuit; c) 2-wires circuit;
The connection circuit should not be changed while unit is powered. Every change
of connection while the unit is powered causes measurement errors by several
seconds after change.
4.4. MAINTENANCE
The unit does not have any internal replaceable or adjustable components available to
the user. Pay attention to the ambient temperature in the room where the unit is operating.
Excessively high temperatures cause faster ageing of the internal components and shorten the
fault-free time of the unit's operation.
In cases where the unit gets dirty do not clean with solvents. For cleaning use warm water with
small amount of detergent or in the case of more significant contamination ethyl or isopropyl
alcohol.
Using any other agents can cause permanent damage to the housing.
Product marked with this symbol should not be placed in municipal waste. Please
check local regulations for disposal of electronic products.
10
!
Pt100
Ra Rb Rc Rd
Ra, Rb, Rc, Rd can be different
21 22 23 24
Pt100
Rb Rc Rd
22 24 23 21
Rb = Rc = Rd
n.c.
i
i
Pt100
Rb Rc
22 23 21 24
Rb, Rc can be different
n.c.
n.c.