TT_ZX

Works much better than putty, thanks. Now I can disconnect and reconnect without having to close the window.

Thanks for the tip. I've been using putty but this looks very good. I'm going to give it try tonight.

I have the same problem with Spirax Sarco pneumatic positioners. I use the Seneca K109UI to overcome this problem but most isolating transmitters should cope. http://www.senecauk.com/acatalog/K109UI.html The K121 might also work for 4-20mA and is cheaper for me. http://www.senecauk.com/acatalog/K121__Universal_Isolated_Transmitter_with_2_Wire_-_Loop_Powered.html

Couldn't you just store a value (say 0) into all of the MI's linked to the analogue inputs on power up? This way you can detect that the MI's are not being updated.

If you are referring to the SQM45 and SQ48 then no these won't work. They use a proprietary Siemens version of canbus that can only be used with the LMV5x burner managers. I uses these all the time along with the LMV5x and they would have been perfect if they worked with the standard canbus.

Can anyone recommend a quarter turn canbus actuator for use with a V1040. I need about 20 Nm of torque. Any suggestions of brand or model etc would be greatly appreciated.

My issue is with loop powered positioners. I wouldn't expect problems with self powered positioners. It seems as though a minimum amount of power is required from the loop for the internal circuitry. Therefore at lower currents a higher voltage is required. Ie 7V x 4mA = 28mW. The impedance in my case is 1750 ohms at 4 mA (7V / 4mA = 1750). Way above the maximum of 500 ohm. Yet at 20 mA the impedance was something like 350 ohms. I think signal generators have a maximum voltage which is available at any current. 10V is all that is required to supply 20mA to a 500 ohm load. 10V could supply 4 mA in to a 2500 Ohm load. I don't know why the Unitronics analog output modules can't supply 7V at 4 mA.

I have the same issue with the analogue outputs not being able to drive a Spirax Sarco SP400 positioner. These positioners require 7V at 4mA. The positioner would not power up until the output is close to 12mA. The impedance of the positioner is inversely proportional to the current. As the current to the positioner increase, the voltage actually reduces. You can test this yourself by putting a voltmeter across the positioner and drive it through the range with the fluke signal generator. I have been using Seneca K109UI or K109S isolating transmitters between the PLC and the positioner to overcome the problem. Expensive, but I don't know of better way. You could range the positioner to work from 9-20mA. This is a bit of a hack that I used with the SP400's until I got the isolating transmitters.

File is too big to upload here so try this link: http://files.butlerfamily.net.nz/Event_Log_Example.vlp

Hi TM Yes I used your alarm module in my last project and it worked great so thanks very much for sharing. The down side of this approach is that the alarms must be static (e.g. predefined in the string library). This was not an issue for my last project and the vector of alarm bits was also a good fit. However my current project is a bit different. The event log I am developing is more for information purposes rather than a set number of fault conditions. The log is displayed on a master PLC that has up to 20 slaves that look after up to 1000 animals. There are several different event types that have different numbers and types of associated variables. I could put all these variables into different columns in the event log (and indeed this is the case with the date stamp), but then some of these columns would be empty and the result is an untidy looking page. I could create several different log types but that's not very user friendly. I have chosen to assemble a string based in the received data and store in a data table. As far as i know you can't store data into the string library like this. It's sounds complicated but its not really. I'm storing events into a data table in 7 nets of code and displaying them on the event log page in 6 nets so far. Thanks, Justin

Hi Keith Thanks for your reply. I am often not very good at explaining things, so I will try again. I am doing exactly what you have explained. The issue I have is that the event message is stored in the data table as a string of up to 60 characters. This string is created by assembly several bits of information before it is written to the data table. When the one message is read from the data table it occupies 30 MI's. If I have 20 of these messages display at a time this will occupy 600 MI's. This seems like a waste of resources to me. So to overcome this I am loading the 1st message into a vector of 30 MI's and then setting the Link MB of the 1st message on the HMI page. The OS then refreshes the display and resets the Link MB. I then load the 2nd message into the same vector of 30 MI's and set the Link MB of the 2nd message on the HMI page. The OS then refreshes the display and resets the Link MB. The process repeats for the full 20 messages. Doing it this way means I am only using 30 MI's instead of 600. As explained in my first post, this works well when I have the Keypad Entry boxed checked but not when it isn't. Cheers, Justin

I am developing my own event log display. I am reading a string from a data table and then displaying it using the ASCII String variable. I am doing this sequentially using the same vector of 30 MI's for 20 rows. I am doing it this way so I don't have to use 600 MI's (30 x 20) to hold the required data for the full display. If i have the keypad entry box ticked in the ASCII String variable everything works perfectly. However, if I un-tick the the box the variable keeps updating automatically. This overwrites my messages with whatever is in the last message. This is not helpful because I don't want the keypad entry. What is the purpose of the Linked MB when the keypad entry is not ticked? It seems to me it has no use if the variable is update automatically? Does anyone know of a work around to either disable the keypad entry or the automatic updating? Does anyone know of a better way to achieve the same thing? The messages are generated dynamically based on several pieces of data so I can't use the string library.

The PLC tripped when the comms failed while the PLC was running, which is the expected behavior. If there is no comms to the EX-A2X when the PLC is powered up, then the PLC will run. This is also the expected behavior and is great for testing purposes. This doesn't present any safety concerns because all the outputs are off. The problem with mixed I/O on snap-on and EX-A2X I can't help with. This is not something I have done before and wouldn't want to anyway. Sorry I can't be of more help. Cheers, Justin

Hi Kieth Thanks for your comments. The burners are actually Oilon not Weishaupt. I have used Weishaupt burners for many years in the last company I worked for (they have the agency in New Zealand) and actually had training in their factory Schwendi, Germany. It's generally accepted that Weishaupt make the best burners in the world and from my experience I would generally agree. The smaller oilon burners are also very good but don't have the polish of the Weishaupt burners. The Oilon burner used in the large boiler I would argue is better than a Weishaupt of equal size. I was very impressed during commissioning on how well in performed. You are spot on with the flame safeguard. There is a Siemens LMV52 mounted in the burner. I have been using theses for years and they are excellent. These burners have VSD fan speed control and O2 trim. I have the V1040 connected to the AZL (HMI for the LMV5x) with RS232 and retrieve data via modbus. The small boiler was my first Unitronics project and the large boiler is my second. I am hopeless at drawing but with the right software a seem to be able to make something presentable. I use AutoCAD for vector graphics (and for electrical schematics) and Paint.net for rendering. A basically start off with a 800 x 600 canvas and then build all my graphics in layers. I then flatten this image and use it as a background. I can then just cut out parts of it to create variable images and colour them to suit. I try to work with images at the exact scale they will be used on the PLC so that scaling is not required. Scaling messes up the graphics at these resolutions. I have learnt a lot over the last 18 months. Cheers, Justin

Here is a large package boiler our company has recently completed. This is a 14 MW water tube boiler supplying 20,000 kg/hr of steam at 22 bar. This boiler is complete with de-aerator which is large enough for a 2nd boiler. All motors are on VSD's and the plant was design to be as efficient as possible. Boiler is fired on LPG with diesel as a backup.

Finished this small package boiler project a year ago now. Boiler has been running great since then. The boiler is 2.1 MW producing 3,000 kg/hr of steam at 10 bar. The PLC is a V1040 with Modbus comms to a Siemens LMV52 burner manager. The system includes a GSM modem for alarm SMS messaging. The client is very happy with the plant.

I've had a corrupted background image (after changing it) once since upgrading to 9.4 on a v1040. I fixed it the same way you did.

Thanks for your help Alex, this was the problem and my application is now working. I never found any mention of null-terminated file names in the documentation. I just assumed that because the file name must be in 8.3 character format it would require 12 bytes or 6 MI's.

Tried both upper and lower case but no luck. Thanks for your input.

Here is a program demonstrating the problem. SD_Card_Trend_Read_Write_Append.vlp

This is for a trend file. I'm trying to rename it from TREND100.UTR to TREND101.UTR. I stop the Trend To SD utility before trying to rename the file.

I cannot get the SD Utility Rename File to work with an indirect Old File Name. If I enter the Old File Name directly it works. The New File Name is indirect in both cases. I even put an ASCII String on the HMI to check the Old File Name and it is being displayed correctly. I am using 6 MI's to hold the 12 characters of the 8.3 format file name. The status message is 16 which is bit 5, "Path not found". Does anyone have any tips on solving this?

Thanks bc_fred. I won't be doing the doing the Intouch work. I have read in another post that you cannot limit what areas are written to when the PLC is set up as a Modbus slave. Do you know anything about this? Can the PLC be setup in a read-only mode? Thanks, Justin

I have a customer that wants to retrieve data from our V1040 using Intouch scada. I haven't done this before so if anyone can give me pointers on what documentation to read to get up to speed it will be appreciated. What protocols should be used and what are the pros and cons? Thanks, Justin

I had a customer ring yesterday with an error on the screen: Stop Mode Fatal Error 003.004.00 No Application It seems that the PLC lost its memory while it was powered up and running. I haven't been backing the program up to flash for various reasons. Has anyone seen this before. I checked the battery and this was ok, not that it should matter because the PLC was powered up the whole time. I have seen PLC's get corrupt memory before but never lose there memory completely. What happens if the memory in the V1040 gets corrupt?