Simex SUR-94, User Manual

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User manual - METER SUR-94
Figure 4.16. Connection of voltage converters
Temperature sensor can be connected to the device in typical 4-wire circuit ( Figure 4.17a ) or
3-wire circuit (
Figure 4.17b
). 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
Ω
.
a) b) c)
Figure 4.17. 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
breaks are detected within about 2 seconds. For connectors number 32 and 33 of
RTD input it may take up to about 7 seconds. During detection measurements will
be incorrect. If wire break is detected
"S.Err" (sensor error) message is displayed.
15
+ -
5 6
24V DC
+ -
internally connected
-
+
+
+
-
+
31 32 33 34 35
31 32 33 34 35
i
i
RTD
Ra Rb Rc Rd
Ra, Rb, Rc, Rd can be different
31 32 33 34
RTD
Ra Rc Rd
Ra = Rc = Rd
n.c.
31 32 33 34 31 32 33 34
Ra Rc
n.c.
RTD
n.c.
Ra, Rc can be different