Timer Off Delay.
Previously we talked about the timer on delay; now talk about timer off delay (TOF). At the end of the post it will show an example of a level control of a tank using timers. The timer is an output…
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control
Two and three-wire connection
Sensors with digital output to function properly need to consume power for operation of the control circuit. Furthermore, the output circuit must complete a loop with the power supply and the load. This is done connecting to two wires o…
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DCS or PLC or PAC or RTU?
One often hears the question what is the difference between a PLC and DCS?, or question what is the difference between a PLC and RTU? This article the differences between these devices are clarified. Programmable Logic Controllers (PLC) The PLC…
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Sensors. Output Types.
In previous post it mentioned that the sensors have digital and analog outputs, however sensors also may have serial outputs, which can send digital, analog signal or both. Digital output An important aspect to consider is the type of output…
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Operator interface
What is an operator interface? An operator interface is a device (or more) by which the operator gives orders to the controller of a process and receives from the controller the process current state. Operator interface levels There are a…
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Timer (On Delay).
The timer is a output instruction, therefore, placed in the last position of the line. There are three types of timers: on delay (TON), off delay (TOF) and on delay retentive (RTO). Each timer has a time base that can be…
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Driver configuration. Download PLC program
Download the program to PLC or PLC emulator is done in two stages. The first stage is to configure the communications driver RSLinx. The second stage is the download from RSLogix to the PLC. Communication driver configuration 1.Open RSLinx and…
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RSLogix Micro. Common operations
RSLogix Micro is used for configuring the programmable logic controllers of the family 1000 and 1100, it works under Windows and has a very nice user interface and easy to use. Below the most common actions in the development of…
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PLC: my first steps
The access to the data memory is different to each PLC. There are many marks and models of PLC. Some popular marks are Allen Bradley, Siemens, schneider-electric, Omron, Automation Direct among other. It is very difficult to talk about to…
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Memory and scan cycle.
The processor or CPU is the more important part of the controller; it is the responsible for executing all tasks for which it was schedule through instructions and data that are locate in the memory. The controller memory is split…
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