Rockwell Automation 1756-CFM ControlLogix Configurable Flowmeter Module - Manual (Page 139)

139 Rockwell Automation Publication 1756-UM010B-EN-P - December 2011
Schematics 139
Output Circuits
The CFM module provides two output circuits.
Discrete Outputs
The CFM module’s outputs are comprised of isolated power MOSFETs.
These devices operate in current sourcing mode, and are capable of delivering
up to 1A (@ 10-31.2V DC) and 20mA (@ 5V DC).
The CFM module contains two output circuits. Customer supplied power, ranging from +5V to
+31.2V DC, is connected internally (through terminals #18 and 20) to the power output
transistors. When an output is turned on, current flows into the source, out of the drain, through
the load connected to the ground of the customer supply (customer return). Diode D26 protects
the power output transistor Q11 from damage due to inductive loads.
Output transistor Q11 is thermally protected power MOSFET and will turn off @ 4A
(approximately). After an output goes into thermal shutdown, you must fix the cause of the
shutdown and toggle the output OFF and ON to reenergize the output.
42847
Vcc
R159 R108 U20
R109 D25 D24
D26
F1
Output 0
Customer
common
Customer
Vcc
16
19
18
Output FET
Output 0
physical and electrical isolation
Output 1
20
15
17 Customer
common
Output 1
Customer
Vcc
Q11