Emerson ROC827 - Manual (Page 84)

ROC827 Instruction Manual
Issued Mar-06 Input/Output Modules 4-14
+
-
OPEN DRAIN TYPE
OR
OPEN COLLECTOR DEVICE
EXTERNALLY POWERED
+
-
CONTACT-CLOSURE DEVICE
EXTERNALLY POWERED
12KHz PI FILTER &
LEVEL DETECTION
12KHz PI FILTER &
LEVEL DETECTION
DOC0510A
Figure 4-12. Externally Powered Pulse Input Module Field Wiring
+
-
12KHz PI FILTER &
LEVEL DETECTION
+T
METER COIL
- +
DOC0511A
H
L
H
L
C
O
M
C
H
2
C
H
1
+
T
PI
2 CHAN
OPEN DRAIN TYPE DEVICE
OR
OPEN COLLECTOR
ROC800 POWERED
C
O
M
Figure 4-13. ROC800-Powered Pulse Input Module Field Wiring
Note
: All I/O modules are isolated on the field side. Be aware that you can
induce ground loops by tying commons from various modules together.
4.9 RTD Input Modules
The Resistance Temperature Detector (RTD) module monitors the
temperature signal from an RTD source. The module can accommodate
input from a two-, three-, or four-wire RTD source.
The active element of an RTD probe is a precision, temperature-dependent
resistor made from a platinum alloy. The resistor has a predictable positive
temperature coefficient, meaning its resistance increases with temperature.
Representative
Internal Circuit
Field Wiring
Representative
Internal Circuit
Field Wiring