For this application, I use Omron PLC CP1L with external
analog input and digital output as digital battery level indicator with 4 levels
for 6 volt battery.

Download PLC Program File:

See the video for this application:

**A. Wiring Diagram between Battery, Analog Input PLC, and Digital Output PLC of Omron PLC CP1L**

**A.1.**

**Preparation**

**1. Omron PLC CP1L-L10 with external analog inpu**t

**2. External Analog Cable**

**:**

*Remarks*
Black color to negative battery

White color to positive batteryy**3.**

**Battery DC 6 Volt for Testing**

For this application, I use battery dc 1.5 volt as
many as 4 pieces.

**A.2. Installation**

**1. Battery to Analog Input PLC**

**2. Accumulator to Analog Input PLC**

**B. Information about External Analog Input of Omron PLC CP1L**

Analog voltage values 0 volts to 10 volts can be
digitized with 0 to 255. Digitized values are sent to the A643 of Omron PLC CP1L.
The following is relationship between Voltage Values and A643.

**C. 6 volt and 4 levels battery indicator to digitized**

The following descriptions:

**1.**10 Volt digitized = 255

**2.**6 Volt digitized = (255/10) X 6 = 153

**3.**6 Volt per 4 Levels (Per Level) digitized = 153/4 = 38.25

In PLC Programming: Because per Level there is 2 digits after
point, and then 153 multiplied by 100. And Value for per Level = (153 X 100) /
4 = 15300 / 4 = 3825 (this value no point and suitable for PLC programming)

**4.**The values of each level become:

4. a. Level 1: (153 X 100)/4 = 3825 is the digital
value of analog 1.5 Volt of battery

4. b. Level 2: (153 X 100)/3 = 7650 is the digital
value of analog 3 Volt of battery

4. c. Level 3: (153 X 100)/2 = 34425 is the digital
value of analog 4.5 Volt of battery

4. d. Level 4: (153 X 100)/1 = 15300 is the digital
value of analog 6 Volt of battery

**5.**PLC Programming for per levels of Battery Level Indicator

5. a. BufferA643 = A643 X 100

5. b. Level 1: If (BufferA643) >= 3825) Then Digital
Output 100.00 = ON

5. c. Level 2: If (BufferA643) >= 7650) Then Digital
Output 100.01 = ON

5. d. Level 3: If (BufferA643) >= 34425) Then Digital
Output 100.02 = ON

5. e. Level 4: If (BufferA643) >= 15300) Then Digital
Output 100.03 = ON

The following is relationship between battery level
indicator and Digital Value (A643) of Omron PLC CP1L.

**D. Digital Output Light Lit for each Level**

**E. Ladder Program for Battery Level Indicator**

**Click Here****F. Video about make ladder program for Battery Level Indicator****G. For other battery voltage**

Battery voltage greater than 10 volt should use
additional resistors, e.g. 12VDC, etc.

In this case use

*Kirchhoff's*Voltage*L**aw**(KVL)**See the picture below:***,****Example Battery Voltage (V) =12volt**

Defined:

V=12 volt

R2=1000 ohm

V2=10 volt

Then:

I=V / (R1+R2)

I=V2/R2

V2/R2 =V / (R1+R2)

V2(R1+R2)=V*R2

V2*R1+V2*R2=V*R2

V2*R1=V*R2 – V2*R2

R1=
((V-V2)*R2)/V2

R1=((12-10)*1000)/10

R1=2000/10

R1=200 ohm

Watt Resistor (Standards: 1/8W, 1/4W, 1/2W, etc.)

I=V/(R1+R2)

I=12/(200+1000)

I=0.01A

Watt R1=I*I*R1=0.01*0.01*200
= 0.02watt = 1/8W

Watt R2 =I*I*R2=0.01*0.01*1000=0.1watt
= 1/4W

For Battery Voltage=12volt uses R1=200 ohm 1/8W and
R2=1000 ohm 1/4W

For other battery voltage, you can try with way the
above.