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Search: Posts Made By: lfe
Forum: LIVE PLC Questions And Answers February 24th, 2021, 04:35 AM
Replies: 10
Views: 386
Posted By lfe
Address 40001 or 400001, with 6-digit addressing,...

Address 40001 or 400001, with 6-digit addressing, in the Holding Registers field, corresponds to offset 0, address 40000 does not exist.

The relationship between internal registers of your PLC,...
Forum: LIVE PLC Questions And Answers February 22nd, 2021, 01:20 PM
Replies: 26
Views: 1,105
Posted By lfe
I would disassemble all the electronic equipment...

I would disassemble all the electronic equipment and put them in a drying chamber, which can be something temporary, a small space with a domestic heater and not well closed since the air has to be...
Forum: LIVE PLC Questions And Answers February 19th, 2021, 04:13 PM
Replies: 11
Views: 402
Posted By lfe
There are several protocols called Ethernet/IP, ...

There are several protocols called Ethernet/IP,

Tag based one uses explicit messasing and is applied to exchange data from PLC with SCADA/HMI or PLC with PLC.

Ethernet/IP implicit messasing...
Forum: LIVE PLC Questions And Answers February 19th, 2021, 03:00 PM
Replies: 11
Views: 402
Posted By lfe
TCP/IP is not a protocol, it's a transport layer,...

TCP/IP is not a protocol, it's a transport layer, TCP/IP connects a client to a server and allows bytes to be sent and received in both directions but then they need a protocol and Ethernet/IP* is...
Forum: LIVE PLC Questions And Answers February 17th, 2021, 10:15 AM
Replies: 12
Views: 506
Posted By lfe
https://open62541.org/ is free

https://open62541.org/ is free
Forum: LIVE PLC Questions And Answers February 17th, 2021, 09:46 AM
Replies: 12
Views: 506
Posted By lfe
With one of the OPC UA Server SDK available on...

With one of the OPC UA Server SDK available on the market, a experienced programmer could develop what they ask for, only that instead of reading the data from the plant's devices, he would read them...
Forum: LIVE PLC Questions And Answers February 16th, 2021, 03:00 PM
Replies: 37
Views: 1,791
Posted By lfe
In addition to what was said by others: ...

In addition to what was said by others:

Check the devices manual about how much free space it need around, but never less than 25 mm between the devices and the cable duct. This space is necessary...
Forum: LIVE PLC Questions And Answers February 15th, 2021, 12:45 PM
Replies: 8
Views: 426
Posted By lfe
I used in early 2000's some GSM modems connected...

I used in early 2000's some GSM modems connected to the PLC through an RS232 port.

You have to compose and send the appropriate character string to the modem and that's all.

Of course, in your...
Forum: LIVE PLC Questions And Answers February 14th, 2021, 05:19 AM
Replies: 8
Views: 644
Posted By lfe
With the progressive implementation of IEC 61131...

With the progressive implementation of IEC 61131 on which the variables (tags) of the program no longer have to be linked to a physical address and are referenced by name, I clearly believe that in...
Forum: LIVE PLC Questions And Answers February 13th, 2021, 09:17 AM
Replies: 133
Views: 6,028
Posted By lfe
Totally agree. When PLCs began to be able to...

Totally agree.

When PLCs began to be able to make floating point calculations I made my own regulation algorithm, one that I really did understand and it worked much better than the previous one....
Forum: LIVE PLC Questions And Answers February 13th, 2021, 08:10 AM
Replies: 133
Views: 6,028
Posted By lfe
I have seen some PID algorithm in PLCs and also...

I have seen some PID algorithm in PLCs and also in panel temperature controllers in which the derivative effect makes that rebound that you describe but the sum of both corrections usually goes in...
Forum: LIVE PLC Questions And Answers February 12th, 2021, 05:55 PM
Replies: 133
Views: 6,028
Posted By lfe
The parameter that will close the valve before...

The parameter that will close the valve before the temperature is exceeded is the derivative factor D that acts not by the error value (PV - SV) but by its variation.

You would have to play with...
Forum: LIVE PLC Questions And Answers February 9th, 2021, 08:12 AM
Replies: 24
Views: 871
Posted By lfe
To get an accurate pulse every second I have used...

To get an accurate pulse every second I have used this method, without using a timer:

- When entering RUN mode I copy the the system clock seconds in a register

- On each scan I compare the...
Forum: LIVE PLC Questions And Answers February 7th, 2021, 04:15 AM
Replies: 24
Views: 871
Posted By lfe
For a totalization calculation (Integration)...

For a totalization calculation (Integration) having a precise time base is essential

In both examples that you have shown, the time calculation is not very precise since it will count the timer...
Forum: LIVE PLC Questions And Answers February 4th, 2021, 04:31 PM
Replies: 22
Views: 1,054
Posted By lfe
Use a PLC output to generate periodic pulses that...

Use a PLC output to generate periodic pulses that restarts an external electronic timer, if the PLC stops the timer output will trigger an alarm
Forum: LIVE PLC Questions And Answers February 4th, 2021, 05:52 AM
Replies: 7
Views: 388
Posted By lfe
OPC UA foundation specs have a whole part...

OPC UA foundation specs have a whole part dedicated to Security.

It is a different and more complicated protocol but it may serve as a guide
...
Forum: LIVE PLC Questions And Answers February 4th, 2021, 03:52 AM
Replies: 7
Views: 388
Posted By lfe
Ethernet/IP is an unencrypted protocol and...

Ethernet/IP is an unencrypted protocol and without intrinsic security.

Therefore it should not be open to connections from the WAN and it is usually not exposed to DoS attacks ... except if the...
Forum: LIVE PLC Questions And Answers February 3rd, 2021, 03:00 AM
Replies: 22
Views: 1,182
Posted By lfe
Gateway acting on the one side as Modbus RTU...

Gateway acting on the one side as Modbus RTU Slave and on the other as Modbus TCP master exist on the market, but I doubt that there is one that does that conversion of addresses that you request.
...
Forum: LIVE PLC Questions And Answers January 30th, 2021, 07:26 AM
Replies: 15
Views: 822
Posted By lfe
Ideally, in ground wiring, it is an arrangement...

Ideally, in ground wiring, it is an arrangement of connections in star, with the connection to the general ground in the center of the star.

This is better to avoid to create loops, although it is...
Forum: LIVE PLC Questions And Answers January 26th, 2021, 02:41 PM
Replies: 44
Views: 2,447
Posted By lfe
I used light blue for the neutral, which is the...

I used light blue for the neutral, which is the same for AC and DC, all the neutral cables for AC and all the 0V cables for DC come from a unique insulated bare copper bar connected in a single point...
Forum: LIVE PLC Questions And Answers January 23rd, 2021, 05:48 AM
Replies: 20
Views: 1,348
Posted By lfe
I have never seen a commercial device acting as a...

I have never seen a commercial device acting as a Modbus master that opens a connection and closes it with each request/response.

I think that can only be achieved with custom software.
Forum: LIVE PLC Questions And Answers January 22nd, 2021, 01:38 AM
Replies: 20
Views: 1,348
Posted By lfe
A custom software running on a PC, Raspberry or...

A custom software running on a PC, Raspberry or even a mobile device could do the job, accept multiple connections on one side, replicate requests on the other side through a single connection, and...
Forum: LIVE PLC Questions And Answers January 20th, 2021, 04:03 PM
Replies: 14
Views: 552
Posted By lfe
I loved the simplicity of Mitsubishi ladder, just...

I loved the simplicity of Mitsubishi ladder, just one type of timer for any kind of timing.
Forum: LIVE PLC Questions And Answers January 13th, 2021, 01:26 AM
Replies: 14
Views: 1,106
Posted By lfe
Not in Europe In the US there are usually...

Not in Europe

In the US there are usually motors on which the windings can be connected in pairs in parallel or in series and the voltages at which they can operate have a factor of 2 between...
Forum: LIVE PLC Questions And Answers January 10th, 2021, 02:37 PM
Replies: 8
Views: 786
Posted By lfe
Both AC and DC coils accumulate energy that is...

Both AC and DC coils accumulate energy that is released on disconnection with a voltage spike that can produce a spark in the relay contacts. This is how engine spark plugs work.

As other said for...
Showing results 1 to 25 of 500

 
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