How to call on onboard processor analog input

[Jrivers010]

I am using the free RSlogix micro starter version. trying to play around with SCP to get a better feel for it.

I have it set up like this http://imgur.com/a/wWDrz

the Udemy instructor seems to freely switch this around in "remote run" mode seen here http://imgur.com/a/oPr7A (marked with arrow)

I used the input address I:0.0 because i thought the 1100 B has 2 analog onboard input. and I:0.0 should call on that, while I:0/0 calls on a digital input.

however, it doesnt seem to work. how do i call on my processors analog input?

 

[mike_dr]

there is no onboard analog, but encoder which is not yet your topic.

micrologix has an onboard/embedded DIGITAL input and output, which is I:0, O:0. add a analog card the next slot,slot 1 or in plc address, I:1. The card is 1762-IF4 as seen in your screen shot.

 

[Helliana]

The Micrologix 1100 does two analog inputs built-in. I believe they are addressed by the words I:0.4 for Channel A and I:0.5 for channel B.

If you expand the size of the of the input data file, it sill tell you which ones are the analog input in the description.

 

[Jrivers010]

The Micrologix 1100 does two analog inputs built-in. I believe they are addressed by the words I:0.4 for Channel A and I:0.5 for channel B.

If you expand the size of the of the input data file, it sill tell you which ones are the analog input in the description.

I am confused on another point now. after you said it, i checked and you were correct. But looking at the data file, it looks like they further break up. (i.e. I:0.0 contains I:0.0/0 - I:0.0/15, which is the EXACT SAME call sign as I:0/0 - I:0/15 it seems. and I:0.1 contains I:0.1/0 - I:0.1/15, which is the same as I:0/16 - I:0/31)

and looking at the analog channel address, like you said either I:0.4 or I:0.5, it looks like they ALSO further break down into 16 parts (I:0.4/0 - I:0.4/15 for analog channel A). so doesnt that mean I technically have 32 analog inputs? (since the same is the case for channel B on the break down?)

 

[Helliana]

A / designates a bit level address. A . designates a word level address.

I:0/0 Is the address of the bit 0 of the word 0 of the input files.

I:0.0 is the value of the word 0 of the input table. This word contains bits I:0/0, I:0/1, ..., I:0/15.

 

[Helliana]

Also, the onboard analog inputs are 8 bit inputs where the expansion cards are 15 bit inputs. This means that a 0 to 10 volt signal will be 0 to 1024 on the built in analog inputs instead of 0 to 32767 from the expansion cards.

 

[Helliana]

Also, if you are unfamilar with the term "word" it is just a collection of 16 bits.

A BIT is a single value. 1 or 0. (An example would be B3:1/0)

A BYTE a 8 bits.
A WORD is 16 bits or 2 bytes. (N7:1 or N7:0.1 -- both are the same address just with different syntax)
A DWORD is 32 bits, 2 words, or 4 bytes. (L9:0)

A bit can only have 2 states, on and off. That is why the are considered digital. Bytes, words, and dwords have multiple combinations of values, therefore are suitable for analog signals. Basically the analog signal is converted into an integer count made up of many bits.

If you use an 15 bit analog input card, the PLC will convert the signal to a 15 bit integer or INT. And INT is defined as word where bits 0-14 makes up a binary number and if bit 15 is true, it inverts the number and makes it negative. So if you apply 0 volts to the card, the plc converts it 0 and places a 0 in all 16 bits. If you apply 10 volts to the card, it will make all 15 bits 1 so the word will be 0111111111111111 in binary which is equal to 32767 in decimal form. If 5 volts were applied, you would get 0011111111111111 which is 16383. This gives you resolution of 0.0003 volts per count.

The micrologix built in analog only uses the first 8 bits of the 16 bit word to create a number, giving you a range of 0000000000000000 (0 dec) to 0000000011111111 (1023 dec). This gives a you a resolution of 0.0097 volts per count.

 

[Jrivers010]

A WORD is 16 bits or 2 bytes. (N7:1 or N7:0.1 -- both are the same address just with different syntax)

how come its not N7:1.0 for it to be the same as N7:1 ??

I guess im still confused on addresses.

so I:0.0 calls a analog since it uses a period. and I:0/0 calls on a bit address since it uses a slash. or so i thought.

so is it actually supposed to be I:0.0/1? which is the same as I:0/1 ?

 

[OkiePC]

how come its not N7:1.0 for it to be the same as N7:1 ??

I guess im still confused on addresses.

so I:0.0 calls a analog since it uses a period. and I:0/0 calls on a bit address since it uses a slash. or so i thought.

so is it actually supposed to be I:0.0/1? which is the same as I:0/1 ?

The chassis slots are numbered which would mean that you can represent up to 16 bits in a single slot without ever needing to use more than just the / as a bit delimiter. But some cards and even some built in I/O systems allow for more than 16 bits per slot. That is why A/B started using the period as a 'word within a slot' designation.

Analog expansion cards might have 16 words (each with 16 bits) of data all squeezed into one slot. So "I:x.y/b" references an input point (single bit) where the slot number is "x", within that slot we are referencing word "y" and bit "b".

Remember that all data in any computer can be boiled down to binary code. Allen Bradley software makes it quite convenient to look at the bits within any integer in the data tables. It may not always be useful to change the radix to binary, but it often is very useful.

You can address the bits within a "N" register, program them individually or all at once. Conversely, you could store an integer value in the address B3:10 (note that is all 16 bits from B3:10/0 through B3:10/15) . The ladder view of the data will show "B" words in the binary radix, and "N" words in the decimal format, so using "B" words for integers is not user friendly when reading the logic, but there is no rule against it.

Another handy thing, you can have a number greater than 16 as the bit delimiter. Depending on how your binary view options are set, the software may convert it for you when you press enter.

B3:10/50 is a legal address. It is the same "bit box" as B3:13/2 (50 is 3 times sixteen plus two, so add three integer word locations to the root address and scoot over two more bits).

Be thankful you don't have to learn on a PLC-5 where the I/O is addressed in octal.

 

[Jrivers010]

I was able to understand that B3:10/50 is the same as B3:13/2 (because i accidently found that out when digging more up on the data table)

but how come that doesnt use any (period) at all to address the word file? is B3:13.0/2 the same as B3:13/2? (using your I:x.y/b notation)

 

[OkiePC]

If there is no period to designate a word within a slot, it defaults to word zero. You can put the ".0" in there if you want, and the software may leave that in there if more than 1 word exists in that element.

 

[Jrivers010]

I see. thank you for the help