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Old August 24th, 2010, 05:47 PM   #1
lonegator
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ERROR - Address must be specified to the bit level

I must admit that it's been awhile since I've written a PLC program so please excuse my ignorance. I am using RSLogix 500 with a SLC. I'm creating a data file for cross-referencing my analog inputs. I thought that I had to use an integer data file for doing this AND that the addresses must be specified to the word level. Because I don't have actual input and output locations yet, I'm just pointing the integer inputs to themselves. An example would be:

---][N30:3------------------------------------------------()N30:3

This is causing the error specified in the title. What am I doing wrong? I'm sure it's something simple. Thanks for your help!
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Old August 24th, 2010, 06:00 PM   #2
Steve Bailey
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You have only specified the address to the word level. N30:3 is the fourth word of the integer file N30. N30:0 is the first, N30:1 is the second, etc.

The contact insruction (XIC) and the coil instruction (OTE) can only be on or off. Consequently they must be referenced to a single bit. You need to append the bit number to the word address like N30:3/00 which would be the first bit of the fourth word on the integer file N30. Adresses at the bit level of N30:3 will range from N30:3/00 through N30:3/15.
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Old August 24th, 2010, 06:02 PM   #3
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N30:3 is an integer, N30:3/X where X = 0 to 15 is a bit. A integer in RSLogix500 is made up of 16 bits. You need to specify to the bit level for the type of instruction you are using above.
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Old August 24th, 2010, 06:02 PM   #4
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Quote:
Originally Posted by lonegator View Post
I must admit that it's been awhile since I've written a PLC program so please excuse my ignorance. I am using RSLogix 500 with a SLC. I'm creating a data file for cross-referencing my analog inputs. I thought that I had to use an integer data file for doing this AND that the addresses must be specified to the word level. Because I don't have actual input and output locations yet, I'm just pointing the integer inputs to themselves. An example would be:

---][N30:3------------------------------------------------()N30:3

This is causing the error specified in the title. What am I doing wrong? I'm sure it's something simple. Thanks for your help!
The instructions you are specifying are Bit Level Instructions, addressed to a Single Binary Bit, with a State of Zero or One. The address you are specifying to go with them is a Word Address which can be either -32768 to 32767 or 0 to 65536. (Hope my memory is good) This is incompatible, and RSLogix is warning you this can't work.

I am not sure what you mean by Cross Referencing your Analog Inputs. Perhaps you can give us some details of what you are trying to do.

Stu....
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Old August 24th, 2010, 06:02 PM   #5
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You are using a word address ( 16 bit word e.g. N30:3)
You have to use a bit address with those instructions e.g. N30:3/0 for your XIC
and N30:30/1 for your OTE.

See pdf below for a little info on data file addressing.

Edit: sthompson types faster then I do.
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Old August 24th, 2010, 06:05 PM   #6
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Wow! I actually typed faster than Mickey for a change.

Edit: I am sure between the two of us, he will have a better idea what is causing his problem.

Stu.....
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Last edited by sthompson; August 24th, 2010 at 06:07 PM.
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Old August 24th, 2010, 06:08 PM   #7
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Quote:
Originally Posted by sthompson View Post
Wow! I actually typed faster than Mickey for a change.

Edit: I am sure between the two of us, he will have a better idea what is causing his problem.

Stu.....
I haven't had my beer yet, but I think its time for one.
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Old August 24th, 2010, 06:14 PM   #8
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Here's mine lol
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Old August 24th, 2010, 06:15 PM   #9
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Well it only 82 and very sunny here, but I agree with you.
I am heading for the door now. Enjoy a cool one Micky, you've earned it.

Stu.....
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Old August 24th, 2010, 06:27 PM   #10
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Many of these integers are going to be capturing/displaying various drive speeds, pressure amounts, etc. If I address to the bit level, that data won't properly display, will it? Again, sorry for my ignorance.
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Old August 24th, 2010, 06:33 PM   #11
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I'm writing the program for a plant start up. Because I'm not onsite until next week and because they want a copy of the program NOW (of course), I'm trying to do what I can to "make up" the inputs/outputs that will be used. We're using an I/O scanner and some ASB module so I can't put in any actual addressing until I'm successfully communicating with the system (right??). I made four data files (DI, DO, AI, AO) for my data. Currently I'm just pointing a data point to itself (as I showed in my example). Once I have actual address locations from the scanner/ASB module set up, I was going to substitute in the cross reference data files I'm setting up now to save having to search thru the program to change everything. (Let me know if all that does/doesn't make sense).
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Old August 24th, 2010, 06:35 PM   #12
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Quote:
Originally Posted by lonegator View Post
Many of these integers are going to be capturing/displaying various drive speeds, pressure amounts, etc. If I address to the bit level, that data won't properly display, will it? Again, sorry for my ignorance.
No, it won't display properly. You will want to use an Integer Word to capture/displaying the Data. i.e. N7:0.

Stu......
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Old August 24th, 2010, 06:38 PM   #13
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But that's how I'm doing it, I thought. I created a data file of N30 and have been addressing them as N30:1, N30:2, etc. It's giving me the error.
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Old August 24th, 2010, 06:39 PM   #14
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Is there any particular reason why you want to use words in an integr file for bit-level instructions instead of the B3 file?

If you feel you must use bits from N30 words for bit-level instructions be careful not to use bits from words that are being used for numeric data.
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Old August 24th, 2010, 06:42 PM   #15
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I need words though for the data I'm trying to transfer/display.
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