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Messages - BC SYSTEMS

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Frequently Asked Questions / Re:Managing IEEE Floating Point Numbers
« on: January 19, 2015, 11:03:04 AM »
Thanks Gary,

I'll give that a try!



Frequently Asked Questions / Re:Managing IEEE Floating Point Numbers
« on: January 17, 2015, 04:01:06 PM »
Ok Thanks

Frequently Asked Questions / Re:Managing IEEE Floating Point Numbers
« on: January 17, 2015, 12:07:55 AM »

Thanks that helped but you still have the signed bit representing a + or - depending on your value.   Can I remove this also without moving the data into the 16/32 bit memory?  Appreciate IEEE is for both positive and negative number representation but the value I'm reading will always be positive.


Frequently Asked Questions / Re:Managing IEEE Floating Point Numbers
« on: January 16, 2015, 12:50:31 PM »

I'm using a fx PLC and reading data from a power meter in the IEEE format. When I look at the variable A# in the online viewer the value is correct "240.5". If I copy this to the LCD I get "+240.50000" but really all I want is "240.50".

I have copied the data from A# to A, multiplied by 10 then used the MOD function to get " 240.50" but this seems a little long winded and uses up the 32 bit variable.

I was wondering if I could truncate the A# string?   Have tried A# = MID$(A#),2,6) but this fails to compile  :'(

Technical support / Re:Periodic TCP Port Closure
« on: October 01, 2013, 01:44:44 PM »

Thanks for the suggestion, I will implement that function in the HMI and see how I get on.

Can you confirm the reboot works on FW 76?


Technical support / Periodic TCP Port Closure
« on: October 01, 2013, 08:10:47 AM »

I'm looking to eliminate some communication errors we seeing on site.  The PLC's are connected via Wi-Fi gateways and sometimes the SCADA HMI looses connection and doesn't always re-connect.

I'm not sure if the PLC or the SCADA are to blame or if the Wi-Fi gateways are adding latency which is upsetting things.

So, to try and solve the issue via the process of elimination,  I'm would like to add a small function to close all tcp traffic and if need be restart the PLC, I was looking at setsystem 251 but this only works on FW78 +PLC's.  Some of the PLC's I have are FW76, 77 & 78.  I like to keep my code consistent in all the PLC's so was looking for some advice.

I could periodically call a reset function but I'm not sure if this will close the TCP sockets, does PRINT #4 "</>" close incoming connections?



Technical support / Re:Dynamic text
« on: April 19, 2013, 06:06:52 AM »
Hi Sparky,

See attached.

I have a datamem14 variable in the html code.

look at function modetext below.


function modetext() //IM NTC BB
i = document.getElementById('datamem14').value;
if (i == 1)
document.getElementById('modeIM').value = "Manual Mode";
else if (i == 2)
document.getElementById('modeIM').value = "Auto Mode";
else if (i == 3)
document.getElementById('modeIM').value = "Test Mode";
document.getElementById('modeIM').value = "Off Mode";


Good Luck.


Technical support / Re:Modbus TCP Slave problem
« on: April 19, 2013, 05:58:35 AM »

Version 78A was a problem for me.

How are you thinking of triggering the reboot command?


Technical support / Re:Dynamic text
« on: April 18, 2013, 01:19:45 PM »
Hi Sparky,

I have got dynamic text working and a dynamic picture in a webpage I've developed.

The n.js file has been scrapped and all the js function are included in the HTML file.

I do see communication errors once in a while so I added some code to refresh the page every five minutes which helps keep the connection alive.

I think the next stage is to re-split my code back to a HTML and a js file but its work in progress  ;D

I'll post the code when I'm next in the office that I've used so you can play around with the functions and see what I've done.

I'm no JS or HTML expert, but if you find a good web page forum, most of the members are very helpful. this site is very good for general info The members here were very helpful.

Technical support / Re:Modbus TCP Slave problem
« on: April 18, 2013, 12:57:37 PM »

You can view the FW version once connected to the PLC from one of the top menus, something like " check hardware info"

I think I had a problem with FW version 78A. I will check and come back to you.

Cheers Marcus.

Technical support / Re:I2C Bus Interface Speed
« on: April 12, 2013, 02:51:53 AM »
Thanks Gents.

At least I now know a little more! :-)

Technical support / I2C Bus Interface Speed
« on: April 11, 2013, 02:04:02 PM »

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???


Technical support / Re:Full Duplex RS-232 for Nano-10
« on: March 25, 2013, 07:58:45 AM »
Hi Gary,

Great document. Thanks.


Technical support / Re:Modbus TCP Slave problem
« on: February 05, 2013, 01:19:53 PM »
Ok I'll send over the details.


Technical support / Modbus TCP Slave problem
« on: February 05, 2013, 02:36:07 AM »

I have a problem with some FMD16 PLC's. We have 15 of them controlling pumps around a site and all of them are a little temperamental when responding to Modbus TCP requests.

We frequently have communication errors that require re-booting the PLC's to get the communication going again only for it to fail at some point in the future, this can be 1 day or 1 month...

We use the web server function also and this works fine so I don't think the issue is with the connection more the PLC.

All the PLC's are connected via wifi aerials and generally respond to a ping in less than 100-250 ms so I'm wondering if this is a latency issue on the modbus protocol??  

Can this response time be adjusted??

The TCP master is a SCADA program with polling set to 1000ms for each register / device, with a timeout set to 5000ms.  We only read two registers from each PLC.

The SCADA has a re-connect function that upon connection failure tries to re-connect, this is set to 10000ms.

All of the above work fine when the PLC has been power cycled (a online reset does not help get the communication going :( ) until the comms error returns.

Can I use a set system command on port 4 to set the protocol to modbus without affecting the webserver connections?

The connections are as default 3 server and 3 Modbus connections.

Running out of ideas  
  ??? ??? ???

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