Micrologix 1000 outputs do not activate

df61

Member
D
Join Date
Feb 2007
Location
Lakewood, NJ
Posts
7
Hello,

I have an apparently stupid problem with a couple of Micrologix 1000s I got on eBay. One has 4 outputs and the other has 6. Just for testing, I wrote a little program that turns the outputs on one at a time, then resets everything and restarts. Worked fine on both, then after trying to interface them with a Panelview 300, which I can't manage to do as well, and I don't know why, the outputs on the 4 output Micro stopped working. The 6 output Micro works fine. If I go on line, the rungs controlling the outputs are true, but the outputs don't come on. If I force them, they do. Cleared memory and re-downloaded, no results. What am I doing wrong? Thanks in advance to anybody who might know the answer.
 
Hi, I forgot to say that I'm just learning these things. I had all my outputs controlled in the MAIN_PROG ladder. Then I chose to activate bits instead of directly activate the outputs. I added rungs that activated the outputs when such bits were on. Then I decided to move these additional rungs to a separate ladder, as I saw people doing a couple of times. I think it's a neat thing, instead of having outputs scattered across the program. I didn't add a JSR instruction calling the separate ladder, and that's why it didn't work. Now I have added it and it works. My question is, I think I saw complex programs where the MAIN_PROG ladder only had calls to a few subroutines, while there were other ladders which were running without being called in the main-prog ladder. Am i wrong? I need to find some good manual and read it. Thanks for the time.
 
First thing that comes to mind:

Make sure the rungs are in a ladder that is being executed. Either ladder 2, or a ladder that is jumped to.

I've made that mistake before. I had a seperate ladder for a bunch of lights, and none of them would work, even though the rungs were true. Turns out I forgot a JSR, and the program never entered that ladder at all.

Forcing still works, since that forces the output regardless of logic, but the instructions in the ladder were never executed.
 
I think I saw complex programs where the MAIN_PROG ladder only had calls to a few subroutines, while there were other ladders which were running without being called in the main-prog ladder.
Click to expand...

You can jump to other ladders within ladders that aren't the main. So if you were in ladder 2, and jumped to 3, you could then jump to 5 from 3. You don't have to be in the Main ladder to use JSRs.

So if the other ladders were being executed without being jumped to from the Main, they must have been jumped to inside one of the other ladders.
 
I don't know how much this applies to the ML1000 but in the 1200 and 1500 there can be ladder files that are executed by functions like the High Speed Counter. They aren't called from anywhere in the main (ladder 2) or any sub that it calls.
 
Thanks everybody. Tharon, I got to the same conclusion while you were writing your reply. I also found that I need an isolator to connect the Micrologix 1000 to the Panelview 300. How can Allen-Bradley do such a silly thing, a serial port that's not electrically compatible with their own products! With a simple cable, the two devices don't communicate. They do with a breakout box I have, that's probably isolated. I'll have to get the A-B isolator. Thanks again for your help.
 
df61 said:
Thanks everybody. Tharon, I got to the same conclusion while you were writing your reply. I also found that I need an isolator to connect the Micrologix 1000 to the Panelview 300. How can Allen-Bradley do such a silly thing, a serial port that's not electrically compatible with their own products! With a simple cable, the two devices don't communicate. They do with a breakout box I have, that's probably isolated. I'll have to get the A-B isolator. Thanks again for your help.
Click to expand...

No, you might have the wrong version of Panelview, like a DH485 version instead of a DF1.
 
Think jstolaruk has hit it on the nose. What are the part numbers? The 300's serial port can be flashed to change between DH485 and DF1
 
As I said, I don't know these devices in depth, and I also have a bad luck in everything I do, but my Panelview 300 only has a DF1 port, it only communicates with the ML1000 if I use an active breakout box which I suppose is isolated or conditions the signals in some way, and this is taken from the Panelview manual:

A-B.JPG
 
You don't need it. It is recommended for many devices on the serial network but not necessary for yours. In fact AB makes a cable just for connecting the Micrologix to the Micro 300.

Let's make sure your Panelview is DF1, your Micrologix is setup for DF1, then verify baud rates and Node address
 
Thats for networking. Depending on what version of PV300 you are using, there are different cables for direct connection. Which PV300 are you using?

EDIT: a little slow here, go TW!
 
jstolaruk said:
Thats for networking. Depending on what version of PV300 you are using, there are different cables for direct connection. Which PV300 are you using?

EDIT: a little slow here, go TW!
Click to expand...
That's alright, you can take it from here. I'm tired, going to call it an early night.

My limited knowledge on changing the protocol, but it does give your the document, utility name, and old technote number that you should be able to look up
http://forums.mrplc.com/index.php?showtopic=6905
 
Guys, thanks for the info, I'll check it out. I have a Panelview 300, not a 300 Micro. It's DF1, it says that on the comm. configuration screen. The Micrologix is also obviously DF1. All communication parameters match. I don't think I could program either one from my laptop's serial port if they were 485, right? It might well be that the Panelview has a defective port, after all it's the stuff you find on eBay 'as is', 'pulled but untested' and so on. I even had to replace a fuse (ehm, jumper it) on one of the two Micrologix, because the 24VDC out didn't work. I got these to play with them and learn more about PLCs, and if they work with the isolator I'll be more than happy. Thanks again for your help, now I have to go.
 
You can program a DH485 item from your serial port but that is probably not what your problem is.
Can you see the panelview in RSLinx when you have a direct connection from your PC to the PV?
Regards Alan Case
 

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