Setra System 264 - Manual (Page 2)

2
4.0. CALIBRATION
The 264 transducer is factory calibrated and should require no field adjust-
ment. Generally, the mounting position will have a zero shift effect on ranges
below 1” WC. Whenever possible, any zero and/or span offsets should be
corrected by software adjustment in the user’s control system. However, both
zero and span adjustments are accessible either on the front of the unit or by
removing the optional conduit enclosure. The 264 transducer is calibrated in
the vertical position at the factory.
4.1 Voltage Output Zero Adjustment
While monitoring the voltage between the positive output (OUT) and
common (COM), and with both pressure ports open to atmosphere, the zero
may be adjusted by turning the zero adjustment screw. (See Diagram 1 for
Diagram 4
264
Current
Monitoring
Device
9 to 30 VDC
+
_
Diagram 2
Current Circuit Diagram
3.2 Current Output Units
The Model 264 is a two-wire loop-powered 4 to 20mA current output unit and
delivers rated current into any external load of 0 to 800 ohms. These terminals
have the designation of + and - (See Diagram 3). The current flows into the +
terminal and returns back to the power supply through the - terminal (See
Diagram 4). The power supply must be a DC voltage source with a voltage
range between 9 and 30 measured between the + and - terminals. The
unit is calibrated at the factory with a 24 VDC loop supply voltage and a 250
ohm load.
Diagram 1
Diagram 3
+ OUT Connect to positive terminal of control or pressure
monitor
+EXC Connected to positive terminal of DC power supply
COM Connect as the reference for power supply and
output signal
COM
OUT
Power
Supply
Readout
or
DAS
EXC
Model
264
Voltage Circuit Diagram