Uf251_01d_oi_e.doc / Aug-16
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3.2.
Control Inputs
The unit provides two digital HTL inputs for control of the output frequency. The function of
these inputs depends on the mode of operation. For properties and electrical specifications see
the diagram below.
7,5k
GND
Input
Signal PNP,
Active HIGH
Terminals 8+9
Control Inputs: Properties and principle of circuit
HIGH > 12V
LOW < 3V
Tmin.=
5msec
V
t
Max. 30V
12V
3V
Var.
3.3.
Analog Inputs
GND
100k
Voltage Input
+/- 10V
GND
GND
150R
Current Input
+/- 20mA
GND
GND
+3.9 Volt reference
33k
1k
Potentiometer-Input
Voltage input requires position 5 of the DIL switch to be ON. The input voltage swing
must not exceed the ±10 V range. The resolution is 1 mV and the overall accuracy is
0.1%.
Current input requires position 5 of the DIL switch to be OFF. Terminals 3 and 7 must be
bridged externally. The resolution is 2µA and the overall accuracy is again 0.1%.
For potentiometer input the DIL switch position 5 must also be in OFF position. With use
of a 1kOhm potentiometer, in the centre position of the tap an error of approx. 1%
comes up due to the load by the internal resistance. However, this error can easily be
eliminated with use of the linearization function. For potentiometer supply a highly
stable reference voltage of about 3.9 V is used.
