Internet PLC Forum

Hi,

I'm thinking about using the I2C interface to communicate to a ITG-3200 Gyro IC for a small project.

Now this may seam like a silly question but I have zero experience with I2C devices.......

The Fram I2C documentation says the master operates at 100KHz....  the IC documentation says the IC operates at" bust mode" 400kHz.

Working with what I know about serial communications, Baud rates etc, I'm amusing they will not communicate due to the different communication bus frequencies and the slave device doesn't auto detect bus timing as such.....

Any advice???

Cheers

Hi,

I read in a post some time ago that you were bringing out an analogue module / interface, is this still the case?

Hi,

I'm looking for some webpage help from the support team and the forum community.....

I have modified the standard web pages to suit my needs and I'm having a intermittent issue with the communication.

The page works really well except for the fact every now and then I get a PLC communication JS alert.  I think it has something to do with the communication call vs response latency but cannot pin it down.

The page can run all day without any issues locally or accross the web but then.....bingo comms error.  we have added a refresh after the error alert to get it all going again but its only putting a plaster on things.

 I appreciate that JS issues are not supported and modifications to the standard files are at your 'own risk' as such but I wanted to see if any other users had any JS experience they could share.

I have (against your advice  ) removed the JS file and merged the HTM and JS file into one file.  

The web files and program are attached.  Its a simple time clock program with some fields for entering on / off times of the PLC output with a force option and LCD display.

Anyone with a Nano or F series PLC can install the we page and program and have a go.....  We have a bar graph which also works well.

There are a lot of parts of the HTM file commented out as I'm still testing this and will remove and tidy when I'm done but as said it suits our needs perfectly.

Any JS support welcomed  

Cheers Marcus

Hi,

I need to set the PLC ID from within the PLC program, I've tried SETSYSTEM 8, (&hDM[65]) and a few other permutations but keep getting syntax errors.

I guess the value needs to be in Hex also but cannot see an easy way to convert from dec to hex, plenty of options the other way round or am I missing something?!?

Cheers

Hi,

We use the FMD 16 PLC for a control system and we also utilise the web server function, both work well.

We recently supplied some additional panels which have the same PLC in each but the PLC FW in one panel was r77 and r78a on the other.

The PLC program works the same on both but the web page on the PLC with the later FW shows an asterix (*) on the LCD at the end of the LCD line text see pic.

Any ideas?

Hello all,

I would like to measure a magnetic pick up (MPU) using one of the high speed counters converting the MPU signal into RPM.

The MPU Signal is AC 35 - 55V so will need conditioning prior to being attached to the PLC and I expect to see about 4575 pulses per second so have some questions.

Has anyone done this before and does anyone know if there is an IC or widget that I can use?

Can the PLC actually count the inputs that quickly?

Cheers





 

Evening all.

I have some questions regarding the MBTCP functions within the PLC.

We are using seven nano's to control some pumps in different locations around one of our customer?s site.

The master is also connected to the site SCADA system which views the system status via the web page in the nano.

The topology is one master connected to a tank level sensor and six slave pump panels.

Each panel communicates using a WiFi gateway and the communication is good between all PLC?s.

The master PLC reads the tank level and if the level is above or below the set point, it uses a writemodbus function 1 or a 0 to a DM value in each of the slaves ? simple as that.  Each of the slaves reacts depending on the DM value.

The first question I have is about the number of connections limit.  Is this six for incoming and outgoing connections?

We have set the MBTCP connections to 2 and Server connections to 4. Were assuming the web traffic comes in via the server connection allocation but you know what they say about assumptions!

As described above we have six slaves, when we attempt to connect to a slave, if the connection is successful we call the modbus function above, if the MB write is good we close the connection and move on to the next panel.

We have some error detection code that recalls the function 3 times for both the TCP connection and the MB write before we move on anyway to avoid hanging up the system if one of the slaves is off-line etc.  Every time there is an error or before we connect to the new slave the TCP connection is closed.

This way we are only using one connection to connect to all the slaves which was necessary as there will hopefully be more slaves (panels) in the future.

Second question, when we close the TCP connection does this close all TCP connections in and out?

Third question, is this the best / most efficient way of communicating to each of the slaves?

We have considered using the host link commands but we would still need to open / close the connections as we move around so we thought we would stick with the devil we know. 

The problem we have is the panel locks up completely randomly, sometimes hours, sometimes weeks after a power cycle and I can?t seam to pinpoint the failure because the PLC does not accept any TCP communications and we are not local enough to go in via the RS485.

Any thoughts or wise words greatly appreciated.


Cheers