6 Analog
Outputs
The SCADAPack 350 may include two analog output channels if this option was requested at time
of purchase.
Refer to the TelePACE or ISaGRAF software manuals for information on how to use the
SCADAPack 350 Analog Outputs in application programs. Access to the analog output registers is
achieved using a Register Assignment in TelePACE or I/O connection in ISaGRAF.
6.1 Current
Outputs
The optional analog output module provides two 20mA analog outputs.
The internal power supply powers the analog output circuits. The user can, under program control,
boost the DC Input Power to 24V. This is required when generating current outputs into high
resistance loads. Refer to section
12V to 24V DC/DC Converter Control
information.
Figure 5: Analog Output Wiring
shows example wiring of the analog outputs.
6.2 Voltage
Outputs
To obtain voltage outputs, connect a load resistor in series with the current output channel and the
voltage device across the load resistor. The table below list resistance values and output range
settings for two common voltage ranges. The resistance value listed is the parallel resistance of the
device and the load resistor.
Voltage Range
Resistance
Output Range
0 to 5V
250
Ω
0-20mA
0 to 10V
500
Ω
0-20mA
3
2
1
GND
0
1
P10 - Analog Outputs
–
L
O
A
D
+
–
L
O
A
D
+
Figure 5: Analog Output Wiring
6.3
Analog Outputs Data Format
The optional analog output module has a 12-bit, unipolar, digital to analog converter. There are 4096
discretization steps in the output signal range. The 0-20mA output range resolution is 4.88µA/count.
The table below shows the output current for several data values.
SCADAPack 350 Hardware Manual
February 14, 2007
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