I need advice urgently!!

jolio ST

Member
Join Date
Oct 2004
Location
central CDC
Posts
292
Hello guys.

I am doing this program using Twidosoft. But this is my first time doing this and I have a lot to queried. I hope someone can help me please...I have to get this done by today (Singapore time 7pm, 7am in parts of US).

I have 4 generator control panels, and 1 master control panel. I had already completed the program for the generator panels, but I am confused in the programming of the analog inputs in the master control panel.
I have set the device to communicate by modbus for all panels. and It seem to be working fine. Now here comes my problem.
The 4 to 20 mA signal will come from a power meter of each generator. When a genset is activated, the master panel is to receive the signal and add it to a counter. This counter will have to calculate how many gensets are in operation, and what is the total load they are carrying. but when one of the genset is off, it will also have to update the total number of gensets still on, and the load they are carrying.
I have attached below one of the printsreens of the program. I really need suggestion on how to make the above stated function work using Twido$oft. They have that function on Idec windLdr but not in Twido.
Please help me. Thank you
regards
Sherine T.

11.jpg
 
Last edited:
jolio, first of all lets separate the problems, you stated you need to log on and off each genset. I think your 4-20 ma is representative of current output of the genset.. am I right?
If so then it's safe to say any genset analog output that is 4 milliamps or less input is not "online" or "active".
Use a compare statement to turn on a bit when the current is greater than 4 mills, turn on a memory output bit of that compare to resemble an "on". When the output of the genset drops back to 4 milliamp (or less) then the memory bit turns off"
Then use the memory bit to indicate it is on.

Then use boolean logic to make a count...

example
"if bit0 and not bit1 and not bit2 and not bit3 then count_on = 1"
"if not bit0 and bit1 and not bit2 and not bit3 then count_on = 2"

continue to decode all posible conditions on gensets being on.
Let us here at PLCs.net know if that is what your looking for a start, and keep all of us informed.

ps. this is not code to directly enter it's only to help you. I hope you understand, as so do I hope I understood your question.
 
Last edited:
Hello Bitmore. :oops:
I explain my question further.
A 4-20mA signal from the gensets will be sent to the master panel.
I did a comparison with each input, using the compare block. For each input, I did 2 comparison: less than 35%, and more than 80%, all in decimal format (cos the max for 20mA is 4095 decimal), and send the end result to a memory coil. So if a load % is less then 35% in one generator, and more than one generator is running, the last operated generator will then be shut off automatically. But if the load % is more than 80% on at least one generator, then the next generator will start operation. It can work and do the comparison.
But is/are there any functions you guys can recommend in Twidosoft, so I need not use so much memory(or words) usage.
Please advice. :)

regards
Sherine T.
 
MMMM!!!! The Twido is a very basic PLC to be using for generator control. I normally use Omron CJ1 series, even the bottom end has the same functions as the top end.

I have not looked at the Twido for some time now as it cannot be online programmed. WILL NOT USE A PLC WITHOUT THAT FACILITY!!!!

Do not even have Twidosoft on my computer anymore.

Normally for this requirement I use the ZCMP (range compare) in Omron. It is a compare with a differential. If above the upper value, turn on a bit. If below the lower value turn on a bit. If in between, both bits are off.

Does the Twido have a function like this? Would make life easy if it has.
 
I'm not sure if it has range comparison function in Twido. It's very odd that I do not even see a move command.
Well, I think very few peeps uses this PLC anymore (blame my boss to get such many kinds of PLC products).
I'll just have to fiddle around the stuff, and tell my client to get some days off. :oops:
 

Similar Topics

I'm currently working on a PLC setup and could use some advice on the best way to manage my power supply units (PSUs). Here's the configuration...
Replies
3
Views
370
So, I'm about to start my first ever project that include a servo motor Here some of the component i bought for the project so far: - PLC: Omron...
Replies
0
Views
373
Dear connoisseurs of antiquity and non-standard solutions, welcome) I don’t really hope, but suddenly someone had a deal and, most importantly...
Replies
0
Views
544
Hey guys, We have a metal container at work, we fill with saw dust (20fts x 15fts x 10fts) with the top open but we normally put a container...
Replies
4
Views
1,534
heya guys, For my project, i'm currently looking to add this type of linear encoder. The control company i'm working with told me they had bad...
Replies
6
Views
1,185
Back
Top Bottom