Practical Tips and Techniques
Wiring inputs to the plc like switches and proximity sensors. This also includes analog input signals.
Here’s a Quick Way to Wire NPN and PNP devices I often get asked how to wire NPN and PNP devices to the programmable logic controller. This can be unclear at first when looking at the wiring diagrams. I have managed to destroy a few sensors in the process….. so let’s get started, and I … Read more
Turn a capacitive proximity sensor into a level sensor. This is ideal for tanks and vessels you cannot drill through the side for mounting. Wrap the bare wire around the sensing head and extend it to the length you need to detect. Insulate the wire using electrical tape, but leave the end exposed. This acts … Read more
DC Solenoids are the worse culprits for electrical surges in your system. When the electrically generated field collapses, an opposite polarity voltage is generated. This voltage spike can be high enough to weld the contacts on a PLC output relay. To protect your PLC output relay, use a diode to ensure that the voltage spike … Read more
In industrial environments, we often get noise on the analog signal input to PLCs or other controllers. Motors, lousy wiring, etc., can generate noise. Placing a 1- 100 uF capacitor on the input signal and ground (common to the cabinet) will reduce the noise the input receives. If you have any questions or need further … Read more
The term I/O means Input/Output. I/O can come in two different types; Discrete or Analog. Most people starting out learning about programmable logic controls (PLC) are taught all about discrete inputs and outputs. Data is received from devices such as push-buttons, limit-switches, etc., and devices are turned on such as motor contactors, lights, etc. Discrete … Read more