Current Output Units - Setra Systems 225 Installation Manual

3.2 CURRENT OUTPUT UNITS

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The Model 225 is a two-wire loop-powered 4 to 20 mA current output unit and delivered rated current into
an external load of 0-800 ohms. The Model 225 is available with a multi-conductor cable or various style
connectors. Diagram 3 shows electrical connection wiring for current output transducers.
CONNECTION
+EXCITATION
-EXCITATION
CASE GND
The power supply must be a DC voltage source with a voltage range between 10 VDC and 30 VDC measured
between the "+EXCITATION" and "-EXCITATION". The unit is calibrated at the factory with a 24 VDC loop sup-
ply voltage and a 250 ohm load.
Current must flow in one direction only. Please observe polarity. See Diagram 4.
The cable shield Drain Wire shall be connected to the earth ground to comply with EMC requirements and
electrical noise rejection.
NOTE: The transducer case and integral Bayonet connector shell is electrically connected.
4
See sections 3.3 and 3.4 for addition instructions for units with N1 Output Cable.
CONNECTION TABLE FOR CURRENT OUTPUT TRANSDUCERS
CABLE WIRE
WIRE
RED
BLACK
SHIELDING
MINIMUM SUPPLY VOLTAGE: 10 + 0.02 X LOOP RESISTANCE
MAXIMUM SUPPLY VOLTAGE: 30 + 0.04 X LOOP RESISTANCE
+ EXCITATION
Power
BAYONET
PIN
A
D&B
SHELL
Diagram 3
Setra
Transducer
_
+
- EXCITATION
+
+
_ _
Diagram 4
4 PIN M12 15 PIN DSUB
PIN
1
3
Load
PIN
7
12