M91 Drum not obeying duration time

[Tempus]

I have a M91-2-T38 that I am trying out to evaluate for a project. I am trying to get the drum sequencer to work, but it doesn't seem to obey the duration time.

O/S 91 V3.80 (B09)

Steps to reproduce:

1. Download project to PLC

2. Run the drum by pressing Key #1

What happens:

Drum starts to run, but goes through all the sequences as fast as the PLC can scan.

What I expect to happen:

Drum will run and pause for 10 seconds as per the duration time in the drum sequence.

Any assistance would be appreciated.

temp.U90

[Stein Yair]

Hi,

You should use Positive Transitions and Set Coils.

See Help > Drum for more information.

I fixed your application. Find it attached.

temp-fixed.U90

[Tempus]

Hi,

You should use Positive Transitions and Set Coils.

See Help > Drum for more information.

I fixed your application. Find it attached.

Interesting. The help file doesn't say that you shouldn't use direct coils, but all the examples are with Set/Reset coils. I thought that what I was doing with latching the direct coil was the same as using a set coil. Apparently they have slightly different behaviour at the OS level, even though the boolean logic is the same.

It would be useful to have this behaviour noted in the help section for the drum. Is there someone I should contact for this suggestion or will Unitronics staff take note from this post?

Thanks.

[Stein Yair]

You are correct. Setting SBs does not follow regular logic principles.

We will make it clearer in the help file.