# Basic function principles

KL304x process signals in the range from 0 mA to 20 mA
KL305x process signals in the range from 4 mA to 20 mA
with 12-bit resolution (4095 steps). The terminal inputs are single-ended inputs. The KL3041, KL3042, KL3051 and KL3052 can supply the sensors with voltage supplied via the power contacts. The KL3044 and KL3054 have no power contacts. The power contacts can optionally be supplied via the standard supply or via a power feed terminal with electrical isolation.

The LEDs indicate the operating state of the associated terminal channels.

green Run LED (omitted for KL3044 and KL3054):
On: Normal operation
Off: Watchdog-timer overflow has occurred. If no process data are transmitted by the Bus Coupler for 100 ms, the green LEDs go out.
red Error LED:
On: The limit stop of the A/D converter has been reached. The current is greater than 21.5 mA.
Off: Normal operation

## Process data output format

In the delivery state the process data are shown in two's complement form (integer -1 corresponds to 0xFFFF). Other presentation types can be selected via the feature register (R32) (e.g. signed amount representation, Siemens output format).

Measured value
Output
KL304x
KL305x
dec
hex
0 mA
4 mA
0
0x0000
10 mA
12 mA
16383
0x3FFF
20 mA
20 mA
32767
0x7FFF

## Calculation of process data

The terminal continuously takes measured values and stores the raw values of its A/D converter in register R0 (RAM ). The calculation of the correction with the calibration values takes place after each sampling of the analog signal. This is followed by manufacturer and user scaling:

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

 Y_a = (B_a + X_adc) * A_aY_aus = Y_a (1.0) Neither user nor manufacturer scaling is active. Y_1 = B_h + A_h * Y_aY_aus = Y_1 (1.1) Manufacturer scaling active: (Default setting) Y_2 = B_w + A_w * Y_aY_aus = Y_2 (1.2) User scaling active Y_1 = B_h + A_h * Y_aY_2 = B_w + A_w * Y_1Y_aus = Y_2 (1.3)(1.4) Manufacturer and user scaling active

## Key

Name
Name
Register
Output value of the A/D converter
-
Y_aus
Process data for controller
-
B_a
Vendor calibration: Offset
A_a
Vendor calibration: Gain
B_h
Manufacturer scaling: Offset
A_h
Manufacturer scaling: Gain
B_w
User scaling: Offset
A_w
User scaling: Gain

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

KL304x, KL305x - Data flow