Ab Hsc

Hi, What I am trying to do sshould be simple. I have connected a prox to the first input of a micrologix 1500 and wish to read the switch count into the HSC. The input works but I am not getting an accumulation in the HSC ACC word. The high and low presets are at the max and I have written 1 to the CE (count enabled) bit but still no go. Is there some secret handshake deal that I am not aware of.
I have the mode set at zero which should be count up.
Regards Alan Case

I've never used the HSC in a 1500, but yes, it should be simple... Oh wait, we're talking about A-B...

After a quick look at the manual, things that you might have overlooked are:

1.) Are you sure you've set up the correct HSC? Remember there are TWO in a 1500

2.) From what I read, it seems you need to turn on the "Auto Start" bit in the setup screen to allow operation. Check that it's set to a "1"

3.) We all overlook stupid things sometimes ...You are switching back to "RUN" mode, right? banghead

Other than that, I have no clue... There's a lot of stuff to absorb in that section of the manual!

You may want to search Rockwell's Knowledge Base<--click me for examples. Select "Programmable Controllers" as the Product Group and "MicroLogix1500" for the Product Family, then search for Keyword "HSC". I just checked and there are a handful of examples listed.

Enjoy,

-Eric

If your count rate is fairly quick then the electronic filter may be blocking the signal. Be sure to set the filter time. While OFFLINE go to 'I/O Configurtation', highlight the CPU (just in case you have add-on cards), click 'Adv Config' at the bottom, then choose the 'Embedded I/O Configuration' tab. Set the input filter times then download to the PLC.

Hi all. I got it going by trial and error. I did not have to set the auto start bit but I did have to write a 1 to the Counting Enabled (CE) and the Function Enabled (FE) bit. I was mis-reading what the purpose of the FE bit was used for and did not realise it had to be set to allow the count to accumulate. Thanks to all

Since you're on hsc's. I have seen abit in the instrucion set that i'm not sure how useful it is. The UA. From what I understand you can set this to update the hardware count to the software count.

Is it similar to an STI instruction?

Thanks
Drewcrew6

AB micrologix1500 HSC PROBLEM

I also have a problem in the micrologix1500 serial C.
The counter is working ,but the number is always is negative .
wheither i rotate it clock-wise or anticlock-wise
the number is always is add negative number -1;
is there anyone have prceed it successfully;
please contact me;
my email is [email protected]