Basic function principles

The analog input channels of the KL4494 process signals in the range from -10 V to +10 V with 12-bit resolution (4095 steps). The inputs are single-ended inputs with a common ground potential.

Format of the input values

In the delivery state the process data are shown in two's complement form ( -1integer corresponds to 0xFFFF). Siemens output format can be selected via the feature register R32 as an alternative.

Measured value
Input data
decimal
-10 V
-32768
0x8000
-5 V
-16383
0xC001
0 V
0
0x0000
+5 V
16383
0x3FFF
+10 V
32767
0x7FFF

Process data equations

The process data that are transferred to the Bus Coupler are calculated using the following equations:

Neither user nor manufacturer scaling is active

 Ya = (Ba + XADC) x Aa (1.0) Yout = Ya

Manufacturer scaling active (default setting)

 Y1 = Bh + Ah x Ya (1.1) Yout = Y1

User scaling active

 Y2 = Bw + Aw x Ya (1.2) Yout = Y2

Manufacturer and user scaling active

 Y1 = Bh + Ah x Ya (1.3) Y2 = Bw + Aw x Y1 (1.4) Yout = Y2

Key

 Xadc: Output values of the A/D converter Yout: Process data to PLC Ba ,  Aa: Manufacturer gain and offset compensation (R17, R18) Bh ,  Ah: Manufacturer scaling (Not implemented) Bw,  Aw: User scaling (R33, R34)

The equations of the straight line are activated via register R32.

Analog output channels

The analog output channels of the KL4494 generate signals in the range from -10 V to +10 V with a resolution of 12 bits (4095 steps). The outputs are single-ended outputs with a common ground potential.

Format of the output values

In the delivery state the process data are shown in two's complement form ( -1integer corresponds to 0xFFFF). Siemens output format can be selected via the feature register R32 as an alternative.

Output value
Output voltage
decimal
0x8000
-32768
-10 V
0xC001
-16383
-5 V
0x0000
0
0 V
0x3FFF
16383
+5 V
0x7FFF
32767
+10 V

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 is active

 Ydac = X x Aa + Ba (1.0)

Manufacturer scaling active (default setting)

 Y1 = Bh + Ah x X (1.1) Ydac = Y1 x Aa + Ba

User scaling active

 Y2 = Bw + Aw x X (1.2) Ydac = Y2 x Aa + Ba

Manufacturer and user scaling active

 Y1 = Bh + Ah x X (1.3) Y2 = Bw + Aw x Y1 (1.4) Ydac = Y2 x Aa + Ba

Key

 X: Controller process data Ydac: Process data to D/A converter Ba ,  Aa: Manufacturer gain and offset compensation (R19, R20) Bh ,  Ah: Manufacturer scaling (Not implemented) Bw,  Aw: User scaling (R36, R37)

The equations of the straight line are activated via register R32.