Reading Micrologix I/O and Mapped Fields

[Sudhi Mukherjee]

Just beginning to get familiar with Lookout. I am trying to read/write to mapped fields (B and N) in a Micrologix 1500 PLC. What is the syntax for Lookout to read/write to a channel such as B3:1/0? B3:1/0 is a mapped field for I:1.0/0. Any help is appreciated. I have included my fields list for reference. Thanks.

Sudhi

[steven@ni]

Sudhi,

Here are two links to documents that describe addressing in Allen Bradley PLC's:

http://zone.ni.com/devzone/conceptd.nsf/2d17d611efb58b22862567a9006ffe76/610bb3f26701a1b086256a3a00766ba8?OpenDocument
http://zone.ni.com/devzone/devzoneweb.nsf/Opendoc?openagent&CFE43D8108D49F3C86256A390072A38C

After reading these, please let me know if you have any questions. Thanks.

[Sudhi Mukherjee]

Thanks Steven. I had already looked these up before I posted my question. I guess what I am looking for is:

(1) If the tag in the AB PLC is : B3:0/1, would the corresponding Lookout syntax be: B3:0_1?

(2) If the tag in the AB PLC is : I:4.0 or I:4.1, what is the Lookout synatx for this one?


(3) If the tag in the AB PLC is : C5:0 or C5:1, what is the Lookout synatx for this one?

The examples were not very clear about how to deal with items such as these.

Thanks.

Sudhi

[steven@ni]

I will hopefully clarify the knowledgebase document.

I'll use your example to try to clarify:

If the AB PLC is I:4/0, and you are trying to read the first bit of the fourth module (assuming the fourth module is the 2nd input module), then the correct Lookout syntax would be: I:1_0 (second input module I:1 and the first bit 0).

Remember begin counting modules with 0 and number them with respect to their type.

With regard to your other examples, I assume these are registers or cards (input or output). Again depending on the type of card and the order in the plc, your examples would be:

B3:0/1 = B3:0_1
C5:0 = C5:0

assuming these last two are registers and not i/o cards.

[Sudhi Mukherjee]

Thanks. Will let you know how this turns out.

Sudhi

[Sudhi Mukherjee]

Steven - forgot to mention that I tried the register C5:0 as is (as in your example), and Lookout wont accept that. Does that sound right?

Sudhi

[steven@ni]

It looks like the C registers have a suffix:

C5:0_UA

The suffixes available are: UA, UN, DN, OV, CU, CD,

Also, there are registers: C5:0.PRE (or ACC)

I'm not overly familiar with the allen bradley plc register structure, but these seem to be necessary for lookout to recognize it.