Basic Function Principles - Beckhoff KL4414 Documentation

Basic Function Principles

4 Basic Function Principles
The analog output terminals
• KL4414 and KL4418 generate signals in the range 0 mA to 20 mA
• KL4424 and KL4428 generate signals in the range 4 mA to 20 mA
with a resolution of 12 bits (4095 increments). The actuators are supplied via the voltage fed from the power
contacts. The power contacts can optionally be supplied via the standard supply or via a power feed terminal
with electrical isolation.
Format of the output values
In the delivery state the process data are shown in two's complement form (integer -1 corresponds to
0xFFFF). The feature register R32 can be used to select other display options (e.g. signed amount
representation, Siemens format).
Output value
hexadecimal
0x0000
0x3FFF
0x7FFF
Process data equations
The process data, which are transferred to the Bus Terminal, are calculated based on the following
equations:
Neither user nor manufacturer scaling are active
Y = X x A + B
dac a a
Manufacturer scaling active (default setting)
Y = B + A x X
1 h h
Y = Y x A + B
dac 1 a a
User scaling active
Y = B + A x X
2 w w
Y = Y x A + B
dac 2 a a
Manufacturer and user scaling active
Y = B + A x X
1 h h
Y = B + A x Y
2 w w 1
Y = Y x A + B
dac 2 a a
Key
X: Controller process data
Y : Process data for D/A converter
dac
B , A : Manufacturer gain and offset compensation
a a
B , A : Manufacturer scaling
h h
B , A : User scaling
w w
The equations of the straight line are enabled via register R32.
14
decimal
0
16383
32767
Version: 3.0.0
Output current
KL4414, KL4418
0 mA
10 mA
20 mA
(1.0)
(1.1)
(1.2)
(1.3)
(1.4)
(R17, R18)
(R19, R20)
(R33, R34)
KL4414, KL4418, KL4424, KL4428
KL4424, KL4428
4 mA
12 mA
20 mA