AlanH

When uploading a program to a plc in U90 Ladder to a Jazz there is a warning to confirm that it is safe to stop the plc. Unless I am quite wrong the plc has already been stopped at this stage and the next step is just to start the upload process. I personally think that the timing of the stop signal being sent to the plc should match what appears to be occurring in the program.

When I saw this topic I was hoping it was addressing 1 of my pet peeves but it wasn't. When I write a program I pretty well comments every net which makes it easier to understand 5 or 10 years down the track when a customer wants a change. With other plc types/programs I will commonly print out the program to aid in flicking backwards and forwards to see what I've done where. With Unitronics U90 Ladder the printing is painful. It seems that if there is a comment per net it will then print 1 page per net which with my current program I am working on would equate to 200 pages. Most of what is on the page is a massive Unitronics header and a title block. Despite the "look" of the U90 ladder program looking like it will fit better onto A4 portrait paper it gives you no choice but to print in landscape, with the headers and title block and with 1 comment/net per page. Surely 1 title block in the 100 page printout is enough.

I worked out that I need to reset SB82. Now I have an issue. I am running very low on program space and need to add the 9 consective 16 bit numbers to 9 consecutive 32 numbers. I haven't worked out a recursive way of doing it without gobbling up most of the last 100 instructions I have left to play with. Everthing I have thought of so far uses pretty well all of that 100 and I need some of that 100 for other stuff. For example I need to add MI0 to MI20(MI21), MI1 to MI22(23), MI2 to MI24(25) etc

That's great info thanks Shane. Just out of curiosity does SB2 stay set for the duration of sequencing until reset, for the next instruction or for the 1 net. I've assumed that it's just been for the next instruction but I haven't had a test run of it as yet and without the ability to simulate the process I'm just guessing. Thanks Alan

Hi have a Jazz application where I was hoping to use a MJ20-RS4 with 1 output driving a couple of scales via modbus/RS485 and the 2nd output to drive a serial printer via RS232. Both outputs appear to work fine if I use them separately however every time I poll the scales via modbus I appear to also be sending a character or character group to the printer which is being interpreted as an = . After 80 characters (I think) hit the printer it prints a line of ='s. I only need to print out about 10 lines of text from the printer over a half hour batch whereas the modbus is updating at a few Hz. I can't think of a solution to isolating the 2 ports communications from each other. If necessary I could fiddle with baud rates when I need to swap between devices but that may generate an issue with weird characters being interpreted by the printer. I can't appear to clear the printers cache as it requires an ascii control c code to be sent and it doesn't look like I can put that into a SMS message. Any ideas on how I can stop the extraneous ='s would be great. Thanks in advance.

I have an Jazz application where I am trying to keep track of a hundreds of tonnes of a product in 1kg increments and as such want to use 32 bit numbers. I couldn't actually find it documented if I try using SB82 with addition to handle what will happen when I eventually exceed 16 bits. IF it is as simple as setting SB82 adding MI0 to MI2 and putting the result in MI4. If I am right in my hope that I can do this will it take MI0 and MI1 as an 32 bit number or will it just take MI0. If SB82 doesn't allow for 32 bit addition can someone give me a method of adding a 16 bit number to a 32 bit number for a 32 bit result.

The temp range is a typical Australian outdoor temperature range. It's inside a shed but it's exposed to outside temperatures. It probably has ranged from 0C to maybe 45C. The V280 is in a fan circulated enclosure and is out of direct sunlight. i was hoping that it is a nice easy fix as it's so far away and it's used for a few hours every day of the year.

Hi I've got a V280 plc on a job that's about 1 1/2 yrs old. When i was at the site that's about 150km away last time about 6 months ago the backlight was fairly dim and despite checking that the brightness was set to full the display was still quite hard to read. It now appears the backlight isn't operating at all as the plc display can't be read without ambient light. Is this a common problem? Can anyhting be done to get to get the light going again without major open heart surgery? What sort of life should the backlight get? thanks in advance Alan