102 / 182
ROC800-Series Instruction Manual
Revised Jul-14
Input/Output Modules
4-17
the RTD module. See
Table 4-1
,
Table 4-2
, and
Figure 4-15
.
The ROC800 provides terminations for a four-wire 100-ohm platinum
RTD with a DIN 43760 curve. The RTD module supports RTDs with
alphas equal to 0.00385 or 0.00392
Ω
/
Ω
/
°
C. You can use a two-wire or
three-wire RTD probe instead of a four-wire probe, but they may
produce measurement errors due to signal loss on the wiring.
Wiring between the RTD probe and the ROC800 must be shielded wire,
with the shield grounded only at one end to prevent ground loops.
Ground loops cause RTD input signal errors.
Table 4-1. RTD Signal Routing
Terminal
Label
Definition
1
REF
CH1 Constant Current +
2
+
CH1 Positive RTD
3
–
CH1 Negative RTD
4
RET
CH1 Constant Current –
5
N/A
Not Used
6
REF
CH2 Constant Current +
7
+
CH2 Positive RTD
8
–
CH2 Negative RTD
9
RET
CH2 Constant Current –
10
N/A
Not Used
4-Wire RTD
3-Wire RTD
2-Wire RTD
Figure 4-15. RTD Sensor Wiring Terminal Connections
Figure 4-15
and
Table 4-2
display the connections at the RTD terminals
for the various RTD probes.
Jumper
Red
Jumper
Red
Red
Jumper
Red
White