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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 / 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 / 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  
  ??? ??? ???

Opinions & Feedback / Analogue
« on: December 11, 2012, 04:58:51 AM »

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

Technical support / Email
« on: December 10, 2012, 07:57:25 AM »

I'm using the authenticated email program and it works fine but according to the LCD it says "unknown CMD" and "Email Failed"  even through it works every time?

Z$ is empty as I do not receive a response from my SMTP server. - not sure why?

I have modified the response code of the "ERROR_CHECK" function as below from:

IF STRCMP (Y$, MID$(Z$,1,3)) = 0    ' Check for propper response


IF STRCMP (Y$, MID$(Z$,1,3)) <> 0    ' Check for propper response

The LCD now displays "Response OK" and "Email Sent" but am I just putting a plaster on this or is this what I have to do based on this servers response?


Technical support / Javascript
« on: November 08, 2012, 12:56:46 PM »

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 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  ;D) 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

Technical support / PLC, Modem & SMS.......
« on: September 26, 2012, 06:26:39 AM »

Does anyone have any experience with using the PLC to send SMS messages with a standard modem i.e not GSM?

Can anyone recommend a modem and share some code?  I have been asked to provide this on a very short delivery so I don't want to slip up due to prolonged de-bugging from scratch if possible.

All I need to do is send a text when an input changes state so I'm hoping someone has done this or similar already.

P.s  TL server and a PC is not an option, I need this to be standalone, just the PLC, modem and phone line....


Technical support / Setsystem
« on: August 14, 2012, 02:51:24 PM »

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?!?


Technical support / Input scaling
« on: August 08, 2012, 01:54:26 PM »

I'm trying to read a PT100 via a 4-20 converter but i'm getting the wrong reading.

The converter is scaled 4-20mA, 100Ohm to 198Ohm = 0 to 260 DegC.

I process the 4-20 via a 250 Ohm resistor to get 0-5V

as I see it 260 / 5 (0-5V input) = 52

B = ADC(1)* (2600+520)/4096 - 520

but to get a sensible reading I need to use 650 not 520 but I cannot calculate why??

B = ADC(1)* (2600+650)/4096 - 650

The usable range of the input is 1 - 5 Volts = 0 to 260 deg C as the converter sends out 4-mA as a minimum so I guess this is where my conversion is going wrong!

Any thoughts?

Technical support / FMD FW Revision 78A
« on: June 22, 2012, 02:08:59 PM »

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?

Technical support / MSB LSB
« on: April 11, 2012, 03:39:19 AM »

Can you please assist.

I'm reading some modbus values to DM and whilst I can calculate the right answer with a calculator I cannot get the maths right in  the PLC.

The data is stored in two registers say 40001 and 40002,

If I work in hex the data is represented as 3 and A660  respectively, if I input this into my hex calculator as 3A660 adding the MSB and LSB then change to decimal I get 239200 which is 239.2Volts - fine.

Because the DM's are 16 bit, in the PLC I read 3 and -22944, even if I read the data into the system 32 bit variables as 3 and 42592 I cannot get the maths right to convert back to my required 239200.

I don't need the full three decimal places so will probably divide the number by 100 again so I can store the final value back into DM so my HMI can read the data so temporary use of the 32bit variables would be nice as I have around ten values to convert....

Cheers  Marcus

Technical support / MPU Input
« on: March 22, 2012, 01:07:59 PM »
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?



Technical support / Excel Link
« on: February 15, 2012, 06:46:03 AM »


we have a requirement for the excel link program and we have a copy of the program supplied back in 2004-2005 on CD.

The program version is V1.00 so I looked online to see if there is a later version as per the upgrade.htm file suggests but the server will not authenticate with the excel link user and PW in the htm file?

Is the a later version?  if so, can you re-allow access or email me updated logon details?


Technical support / MBTCP Master
« on: December 22, 2011, 02:33:21 PM »
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. &#61514;

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.


Technical support / Meter Bus (M-Bus)
« on: December 08, 2011, 11:01:49 AM »

Have you interfaced any PLC's with m-bus enabled devices?


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