Scale Ammonia Transmitter (NH3) 4-20mA in PLC Logo
The Analog Inputs 4-20mA are the most electrical signals used for Analog Inputs and we can measure Flow, Pressure, Humidity, etc; in this case will work with a Sensor/Transmitter Polytron 7000 Draeger for AMMONIA NH3
Always consider importants elements:
Identify hardware and Software
CPU PLC Logo! 220VAC or 24VDC (in this case)
Expantion Module Analog Inputs (AM2 AI) Watch Model
Add a Analog Contact AI1 that is the signal from Sensor 4-20mA into Module AI
Add a Analog Amplifier Block to amplify the 4-20mA and transform in 0-1000
Add a Analog Contact with the Address of the first Analog Amplifier, this block has the value 0-1000 already scaled
Add a Threshold Trigger for create a Digital Output in the Software PLC
Add a Digital Contact for ON-OFF Threshold Trigger Block
Create the programm with the follow blocks in Logo Soft Comfort
Let's Configure 4-20mA in 0-1000 and then the Second Scale 0-1000 in 0-300
Scale again in Threshold Trigger block 0-300 and Select >50-ON and <50-OFF
IMPORTANT CONSIDER:
All these Special Sensors as Draeger must to be Configured and Tested by Qualified and Specialist from Draegers or certified Companies
The Signal 4-20mA is scaled in 0-1000 that is the Software Logo Value, remember Wire correctly in the Terminal Current Ix
The Software Value 0-1000 in this case is scaled in 0-300 that is the value CHOOSED by the PLC Programmer; NOTE, this measuremente range is configured from Draeger Transmitter
These Transmitters/Sensor are VERY DANGEROUS because we are measuring Toxic Gases, at moment of get these Sensors, Drager recommend Calibrate Sensor each 6 months or similar
The Measurement of these Sensor are mainly in "PPM", Parts per Million
If we'll work with PLCs Logo 12/24 Volts, remember "Disable" Analog Inputs 0-10 Volts that have somes CPUs 12/24, this in Properties => I/O Settings => Enable 0