Programmable Logic Controller

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1answer
38 views

Monitoring a fan with 2800 RPM with a Siemens 27-226 PLC

I have a fan that rotates at 2800 RPM. I need to make sure that the fan is operating. I need to monitor the fan. It has an output that gives a signal 2 times per rotation so it's 5600 pulses which is ...
3
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3answers
257 views

Digital logic input with very wide input voltage range

We are developing an industrial controls product that will be used to monitor the presence or absence of voltage ranging from 5V to 480V. Since the unit will be generic and programmable, this input ...
2
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1answer
84 views

How to work out or calculate this circuit?

I'm not an engineer, I understand a lot but I fail to understand how it works and how to calculate this for a 24vdc input:
2
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1answer
68 views

When is a programmable logical controller the best choice? [duplicate]

I am studying PLCs as a part of my Elements of Industrial Automation class. Trouble is, I can't imagine why would anyone use such a thing. For complex tasks, microcontrollers are available. The vast ...
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0answers
64 views

Voltage detection / Universal uC Input => CLD, PTC

I'm currently developing a open-source "Home-PLC" for home automation. Every thing runs fine so far and I have a module with fixed voltage AC inputs and outputs. In the next step I want the build ...
2
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4answers
165 views

250 LED control

I am in the process of designing an automated rock climbing wall that will have 250 monocolor LEDs lit in a predetermined pattern that will be changing every 10 seconds. My controller (actually a PLC) ...
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3answers
74 views

Noise on Proximity switch signal on PLC system

I am working on a PLC based system that uses High Speed counter cards to pick up a signal from a 24 VDC proximity switch. I am having a problem with short duration 10 to 15 volt spikes being seen on ...
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0answers
99 views

Noob needs mac OSX based USB PIC programmer to flash eon EN29LV040A PLCC

Please excuse my ignorance of the more technical issues here. I have a Kurzweil synthesizer which has a corrupt flash chip, which I need to reprogram. I would like to know is what PIC programmer is ...
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1answer
265 views

PLC to act as or simulate 4-20 mA transducer

I have a PLC Control system that measures a few 4-20 mA pressure sensors. Today we test these with loop calibrators on each channel. I want to set up a PLC that simulates these pressure sensors so I ...
0
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1answer
223 views

How to stop two DC motors simultaneously using limit switches

I need some help - I'm building a machine but I'm not sure of the best way of doing it. Thanks a million for your help Just to refresh my point - I've made one or two changes I have two large wire ...
2
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1answer
401 views

How to find electrical conductivity from frequency in my PLC project

I am using a 555 timer which is supposed to measure the electrical conductivity of milk. Here's a circuit for a conductivity sensor: It provides the needed isolation, uses AC measurement, and the ...
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2answers
129 views

What does a PLC read if I have an unconnected input?

What does a PLC read if I have an unconnected input? I know that I can test it, but I want to know whether there is any default ?
0
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1answer
194 views

How does a safety PLC work?

I have read the manual, but I am not sure how the omron safety PLC works. I guess this safety PLC use Output Power Supply Output (21,22) to drive the output circuit, but why does it need (1,2) the ...
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1answer
122 views

What is the name of the control system that is PC based PLC? [closed]

I heard people say that PLC can be replaced by computer based gate logic system and has been used in industries for many years. What is the name of that? Thanks
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8answers
8k views

Why use PLC instead of microcontroller?

Why does everyone use PLCs in industrial environments, instead of a microcontroller based solution? For a longer task, the PLC program is as complicated as a microcontroller program. A ...