Simex SUR-W410, User Manual

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User manual - METER SUR-W410
Figure 4.12. Connection of voltage converters
Temperature sensor can be connected to the device in typical 4-wire circuit ( Figure 4.13a ) or
3-wire circuit ( Figure 4.13b ). Due to precision of measurement 4-wire circuit is recommended.
If 2 wire circuit is used, 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
W
.
a) b) c)
Figure 4.13. Connection of RTD sensors:
a) 4-wires circuit; b) 3-wires circuit; c) 2-wires circuit
The connection circuit should not be changed while unit is powered. While using
TC, RTD or voltage inputs (0-150mV) the device is able to detect wire breaks. Wire
14
i
i
18 19 20 21 22 13 14 15 16 17
internally connected
-
+ -
+
+
External power supply
18 19 20 21 22
24V DC
+ -
+ -
+
R
d
R
a
18 19 20 21
RTD
R
a
, R
d
can be different
n.c. n.c.
R
d
R
c
R
b
R
a
18 19 20 21
RTD
Ra, Rb, Rc, Rd can be different
R
d
R
c
R
a
18 19 20 21
RTD
R
a
= R
c
= R
d
n.c.