User manual - METER SRT-94
Figure 4.13. Terminals description (OC-type and active voltage outputs)
Temperature sensor can be connected to the device in typical 4-wire circuit (Figure 4.14a) or
3-wire circuit (Figure 4.14b). 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
4.14c
.
(4-wires circuit with shorted pins 16+17 and 18+19). 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
W
.
a)
b)
c)
Figure 4.14. 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.
14
GND
DATA+
DATA-
RS - 485
+
Uo
-
+24V
+5%, -10%
I
max = 100mA
1
2
5 6 7 8 9
10 11 12 13 14 15
3 4
16
31
17
32
18
33
19
34
20
35
OC1
OC2
- +
OC1 ÷ OC2:
U
max = 30V DC,
I
max = 30mA,
P
max = 100mW
+ - n.c. n.c.
(optional) (optional)
Power
supply
(depending on version)
-
+
ACTIVE
voltage output
(optional)
17 18 19
Pt100/500/1000
Pt100/500/1000
n.c.
i
i
Pt100
Ra
Rb
Rc
Rd
Ra, Rb, Rc, Rd can be different
16
31
17
32
18
33
19
34
Pt100
Rb
Rc
Rd
Rb = Rc = Rd
n.c.
16
31
17
32
18
33
19
34
Pt100
Rb
Rc
Rb, Rc can be different
16
31
17
32
18
33
19
34
Summary of Contents for SRT-94
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