Questions tagged [plc]

Programmable Logic Controller

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50
votes
16answers
60k 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 ...
1
vote
1answer
233 views

WAGO PLC Datasheet I/O' module specs

In "WAGO" PLC datasheet of Analogue and digital I/O's modules what does the following measns : 1- Isolation: 500 V system/supply for analogue i/o module 2- Isolation: 500 V system/field for ...
0
votes
1answer
74 views

Cat 5e, any gauge?

I am working on a double leaf bascule bridge and installing a PLC I/O rack on the farside. The power transmission between the two piers (nearside and farside) is via a single submarine cable (...
6
votes
5answers
5k 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 ...
1
vote
2answers
2k views

safety relays and PLCS

I am having trouble trying to get my head around using safety relays in PLC controlled machinery. I want to install a PLC into a machine that needs upgrading, it is straight forward enough, well i ...
1
vote
2answers
3k views

Can I transmit data over RJ12 to a PC from a PLC?

I have a Click PLC which has two RJ12 ports. I have successfully programmed it using C# and nModBus as a slave, but now I want to test the PLC as a master and the PC as a slave and noticed my laptop ...
0
votes
1answer
55 views

MODBUS RS-485 RTU

can I use this type cable for MODBUS RTU which master 140M far from slaves ?
0
votes
2answers
531 views

Self-Tuning PID Controller to implement in a PLC without having the plant model?

I need to implement a self-tuning PID controller in a PLC. I know the behavior of the plant (I mean, I know that if the speed is reduced the tension gets higher and vice versa), but I do not have a ...
0
votes
1answer
362 views

Using Micrologix 1400 (1766-L32BXB) FET outputs to control frequency input to ST-M5045

There is a minimum current requirement in order to use the FET pins on the Micrologix controller of 21mA, and the output voltage of the pins are 24V. The ST-M5045 stepper driver data sheet says in ...