Best way to set an array to an initial value?

I've got an array valve_set which has a data type of BOOL[32].
I've got another array valve_set_init which also has a data type of BOOL[32].

I'd like valve_set_init to have a constant value of, let's say, [1,0,0,1,1,0,...etc].

At various times, including (but not limited to) at startup, I'd like to make valve_set equal to valve_set_init.

Two questions:
1. What's the best way to set the initial (constant) value for valve_set_init?
2. What's the best way to copy valve_set_init into valve_set?

I've tried the COP (and CPS) instructions, but I get the following error:

Thanks!

This advice pertains not only to your particular application, but everything you will ever program in a Logix-based PLC.

Never use BOOL arrays

They are enormously painful to work with, as you're finding out. Your best bet is to use a DINT. Instead of addressing valve_set[0] through valve_set[31], you'll address it as valve_set.0 through valve_set.31. If you need to use indirect addressing, you use the . and the square brackets - e.g. valve_set.[Pointer]

Once you're using a DINT, COP or MOV will work just fine. COP would be the more "correct" choice.

If you want to be really neat about it, you can set the style to Binary, and then view all of your bits as a string of ones and zeroes still. And if you want to type in a constant in binary, just preface it with 2# (e.g. 2#0000_1000_1011_1100).

1. You can manual set the value or have a MOV instruction set a value for you from another constant with the first scan bit (s:fs).

2. Change your data type from BOOL[32] to a DINT, which will still have 32 BOOL within the DINT. Then use COP, MOV, or FLL as needed.

Thanks!

Thanks to you both, ASF and kay_gsr13! That works!

Question about not using BOOL Arrays

Hi All,
Thanks for your information and help with the problem above. I am curious, however about the apparent lack of support for BOOL arrays. I have found these to be very useful in the past for storing large amounts of data efficiently but I have also found they are not well supported.

If I use DINT sized BOOL arrays it is easy, but what if I want to use a different number of spaces?

itchyspacesuit said:

it is easy, but what if I want to use a different number of spaces?

Click to expand...

I don't understand the question. What do you mean by "a different number of spaces?"

What if I don't want to use DINT-sized buckets?

For example, currently I have an application that uses FactoryTalk view Alarms and Events which requires me to encode on/off switches as bits for each alarm. I have about 500 alarms for each of several phases so using DINTs just doesn't really make a lot of sense.

Does that make more sense?

You would just have to use an array of 32 bit DINTS that has greater than 500 bits (16 DINTS= 512 bits).

I understand what your saying though. I am working on a project with 70 alarms. I've set up a Bool array of 70. I like this because it matches my alarm timer array of 0-70. I'm not 100% sure if FTV alarms will read this correctly but I have Valve_alarms trigger set to bit and the trigger values as shown.