Watlow Series 965 - Manual (Page 9)

Install and Wire, Chapter 2 9
WATLOW Series 965 User's Manual
RTD, 2- or 3-wire
Input Wiring
DIP Switch
Orientation
4 - 20mA Process Input
DIP Switch
Orientation
Figure 11 -
4-20mA Process
Sensor Input Wiring
Figure 10 -
2- or 3-wire RTD
Sensor Input Wiring
Input impedance: 5
Ω
There could be a + 2
°
F input error for every 1
Ω
of lead length resistance when
using a 2-wire RTD. That resistance, when added to the RTD element resis-
tance, will result in erroneous input to the instrument. To overcome this prob-
lem, use a 3-wire RTD sensor, which compensates for lead length resistance.
When extension wire is used for a 3-wire RTD, all wires must have the same
electrical resistance (i.e. same gauge, copper stranded, same length).
ç
CAUTION:
Process input does
not have sensor
break protection.
Outputs can remain
full on.
S1
S2
S3
2
3
5
3-wire RTD
S1
S2
S3
2
3
5
2-wire RTD
Jumper
Terminals
3 and 5.
+
- 2
5
I
d c
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