AB ML1500 Floating point to integer conversion

opamp

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Apr 2003
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Ohio
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In this application I'm trying to convert totalized batch counts over devicenet to a display. The diplay will accept a 4 byte Hex number via (2) 16-bit words through the scanner in a micrologix 1500. With Rslogix 500 I am able to get a conversion from float to 16 bit integer through a MOV command which automatically rounds to the nearest whole number but I can't figure out how to send it into a double word.

:confused: Someone please help
 
The MicroLogix 1500 does support a "Long Integer" 32-bit data type, so maybe try one of those as the target of your MOV command. Since these are batch counts and will be whole numbers, maybe your batch totalizer register should be a Long Integer in the first place instead of a Float.

It's entirely possible that you will have to do some word or byte swapping to get things into the correct order to do to your display on DNet, but we can work with that !

What kind of display is this ? I do a lot of DeviceNet stuff and I'm always looking out for nifty new products.
 
I could be wrong but I don't think that the ML 1500 supports the 32-bit long integer. I may also be thinking of something else. The only reason I decided to use a float F8 is because the batch counts are usually great than 32,767.

The Display I'm using is made by Red Lion (EPAX). It has Extra large, LED, 6 digits, 4" tall, red, 180ft viewable
http://www.redlion-controls.com/
 
Long Integers are one of the niftiest things that A-B added to the MicroLogix 1200 and 1500 that make them more functional than the MicroLogix 1000. They've supported the "L" datatype since release.

I worked with Red Lion's first DNet offering and what I recall about their panel meters was that they were still just that: Panel Meters that took an analog input or pulsetrain input and displayed it. The DeviceNet functionality was strictly to allow that data to be returned to a DeviceNet scanner as well as displayed on the panel. They didn't make a "dumb digit display" that allowed you to send simple DeviceNet output values to be displayed.

[Edit] I don't find any info from Red Lion that says that their PAXCDC30 DeviceNet card functions any differently today than it did two years ago. I'm not sure this display is going to do what you expect it to. Hmm.
 
Last edited:
Sweet!
I had no idea that the long int was available. Thank you guys

As far as the "dumb display", I do have it set up in my office right now and working. In my instance I MOV the data to O:1.5 and O;1.6 which is the scanner memory allocated for this display I also had to set the attribute that I wanted to set. The PAXI requires you to set attribute 9 and then the value in order to send any value to the display.
Go to http://www.redlion-controls.com/literature/bulletins_alpha.html
Check out 12017.pdf

The technical support staff from Red Lion was worthless but I was finally able to get a hold of a EE in R&D from there and he helped me thru it. This works really well on my office floor so far.

Thanks for all. :D
 
Okay, I see how the "dumb display" mode works with the PAXI personality module. Any of the attributes of the PAXI can be forced using the Output command over DeviceNet. In the first byte you put the Attribute number, in the second byte you put the action type (0,1,2 for Read, Write, Reset) and in the remaining 4 bytes you put the value.

The PAXI is the meter version that has a Counter (Counter C) that can be set for slave mode. When you force Counter C, it's Attribute number 9 in the Attribute list.

I agree this would not at all be clear to me if all I had was the PAXCDC and PAXI manuals.

This is great to know about the PAX meters; I've had a few applications where a very simple and durable slave display was needed and I couldn't find one that went onto DeviceNet. If only Red Lion sold a simple "PAX-SRSLV" personality module that would make the device into a display-only module. I guess if I order 200 of them then they'll consider it !
 
It is very interesting Ken that you called the dnet mod a personality module. At least I got a kick out of it. I have just started really with dnet stuff. This is only my third project with... You would think that with an open protocol such as dnet that there would be a little more consistency in setup and functionality. It seems that every third party vendor for the stuff does it a little different, but I haven't played with enough to really say. Suppose this is enough for a different thread but what is your take on the subject.

I haven't done a whole lot with dnet and I've had my reservations about which open protocol to go with. Dnet seemed the logical choice based off of my knowledge of the AB line. But ive played with some S5/S7 stuff as well with Profibus and it seemed pretty nice as well. I know that there are other CAN's yet that would be worth a look but it get's expensive to look at all of this and even more expensive to have all the different hardware/software packages to maintain and program.

Thanks in advance for any input.
 
I look at the complexity of the Red Lion device the other way around; they have a product that can be programmed through a complex menu-driven method, or through a proprietary serial protocol. They adapted that product to a couple of open fieldbus protocols and the complexity of their functionality still shows through.

On the DeviceNet side, they're really as simple as pie; polled I/O with one byte for action, one byte for selection, and four bytes for data.

I am a DeviceNet expert and a Rockwell employee, so I am naturally predisposed to DeviceNet. I use it for everything; sensors, I/O blocks, drives, overloads, MMI.

I am routinely surprised with how little regard third parties give to the PLC's they'll be working with. Any ODVA member in my region has met with me and left with a stack of configuration example documents using Rockwell DNet scanners, which are arguably the most common in the industry.

But I can see their perspective, too; it's not feasible for them to be Omron, A-B, G-E, Emerson, and Entivity programming and configuration experts, and then to do it all over again and become Siemens experts when they want to do Profibus.

I have a hard-hat that I take with me to startups and field engineering projects. There's a big blue sticker on the back that reads "I LOVE DEVICENET".
Underneath it is a smaller sticker reading "soon you will too".
 
Thanks

long integers are one of the niftiest things that a-b added to the micrologix 1200 and 1500 that make them more functional than the micrologix 1000. They've supported the "l" datatype since release.

I worked with red lion's first dnet offering and what i recall about their panel meters was that they were still just that: Panel meters that took an analog input or pulsetrain input and displayed it. The devicenet functionality was strictly to allow that data to be returned to a devicenet scanner as well as displayed on the panel. They didn't make a "dumb digit display" that allowed you to send simple devicenet output values to be displayed.

[edit] i don't find any info from red lion that says that their paxcdc30 devicenet card functions any differently today than it did two years ago. I'm not sure this display is going to do what you expect it to. Hmm.

thanks i was stuck all night
 

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