2
1
PRINCIPLE OF OPERATION
The CI-420 converter has been designed to generate an analog output which is proportional to the
input frequency and at the same time an opto-isolated pulse output the same as the input. All the
mathematical functions are made by a microprocessor that also filters the output to give a stable
reading.
The relationship between the current output and the input frequency is:
I
o
= Output current
I
i
= Initial Current (Beginning of the Scale)
I
r
= Current range
f
e
= Input Frequency
f
r
= Full Range Frequency (Frequency for maximum output)
The value of I
i
(Initial Current) and I
r
(Current range) are selected by means of two jumpers inside the
instrument. The values of these currents for the beginning and full scale are:
Beginning of Scale I
i
Full Scale Current Range I
r
0 mA 20 mA 20 mA
4 mA 20 mA 16 mA
By means of another two jumpers the current output can be changed for voltage outputs to obtain
the following voltage outputs:
Beginning of Scale Full Scale
0 V 5 V
0 V 10 V
1 V 5 V
2 V 10 V
The value of
f
r
(the full scale frequency) is selected by means of four BCD switches below the front
panel. Four jumpers are provided to select the decimal point position.
1.1 Limitations
The minimum frequency that the instrument will detect is 0,04 Hz (one pulse every 25 seconds).
The maximum input frequency is 2.000 Hz.
2.
INSTALLATION
The CI-420 is housed in an IP40 plastic case for mounting on a panel inside an electric control panel.
The plastic case has two holes for mounting with screws to DIN 46 121 and DIN 43 660, and also it
has a snap fastener for fitting to DIN 46 277 and DIN EN 50 022 assembly rails.
Screw terminals are provided for the external wiring. The terminals are protected against accidental
contact in accordance with VDE 0100 Part 750, VDE 0160 Part 100 and VBG 4.
2.1 Mains connection
The mains supply voltage is connected to terminals 1 and 2. The mains voltage is indicated on
the label at the side of terminals 1 & 2.
f
f
x
I
+
I
=
I
r
e
r
i
o
