How can I speed up my Modbus Serial?

[rekholm]

I am setting up a new system to replace an older one.. We are using Zetron RTU's. The controller (1730) is in my building.. a Remote RTU (1716) is at another site. I can talk to it just fine.. All acknowledgements are received, but it won't display on my UI in a very timely fashion! It takes anywhere between 15 seconds and 2 minutes (If it changes at all!).

I started to get im-patient... I clicked the button once, heard the <ACK>, then clicked it again, and it show's that it is toggled right away! Click again to shut it off, and nothing. It stays off for about 5 - 10 seconds, but then reverts back to it's on state. Until I click again, then it goes (and shows) off immediatley! <<FRUSTRATING>>

It seems as though it is the SNAPDELAY function that is doing this, but can't figure out how to set it to longer. Or.. Is this really what I am looking for at all??

Any thoughts or ideas would be appreciated!!

Rod Ekholm

Spokane County Communicatins

[Ryan.S]

The "snapdelay" you said can be solved by connecting the datamember instead of the remote source.

If you connect the remote source, the pushbutton will stay ON and wait for the remote response to confirm. After it gets the response, it will goes off. During this time, if you click it, you may see the behaviour you said.

Try to connect the datamember. Create a pushbutton. Right click it in Object Explorer, and select Edit connections. Select the address and pushbutton to connect them.

But it's not clear why there is a 15sec to 2min delay. You can contact Zetron also for technical support.

[rekholm]

Is there a way to use actual switches instead of pushbutons???  i would rather use a switch that visually has no doubt about what position it is in.

[rekholm]

I got it!! I guess I didn't realize that I had to program the controller unit with some of the same parameters. Once I did this, I set the POLL RATE = 0:01, and it took right off!!

Thanks

[rekholm]

OK..I was a little to sure about this, I guess!!

It seemed to work great for a little while. However now, it is back to it's old tricks.

When I toggle SW1 (000001) to the ON position, I hear the Controller send the assignment to the RTU.. I hear the RTU Ack back. I also have an indicator for 000001. The indicator never goes on, and the toggle switch goes back to it's original state.

The problem is.. if I walk away for about 5 minutes, and look at it again, it now shows it correct ON state. So why the delay??

I created a panel with just OUTPUT#1 SWITCH and INDICATOR (Which happens to be physically looped at the remote site) and INPUT#1 INDICATOR, and it works flawlessly. It reports, then shows the correct states. But with my production process, it takes way too much time.

I have 2 processes running.. A Server and a client. In the server process, is all that I have is one panel and a folder for the Modbus objects (about 32 Modbus Serial). In the Client panel, I use a Symbolic link to get the Input's and Outputs for ewach Modbus device. Is there something else that I need to create in the Server panel? Nobody really needs to look at the "Server" panel as most of the clients will be using the Web view instead in other offices. If I need to see something on the Server, I just look at the client_view, and use it to control features at the remote sites.

Thanks in advance for your help!!

Rod Ekholm

[Rkdomer]

Did you take into account that writing to a register is not the same as reading the register?  In other words, when you turn on the switch connected to 000001 and ‘Immediately write outputs’ is true (by default), Lookout sends the command.  But the status of 000001 will not change until the next poll.  If the poll rate is 1 second you might not notice the delay.  Set the poll rate to 1 minute and you will see the delay.  I’m not clear about what you mean by the toggle switch, I assume you turn the switch on then off rapidly (like a pushbutton).  If this is the case, the modbus object is performing normally as would be expected.

[Mike@DTSI]

Ok i think i know what you are talking about.  Here is what we have obeserved.

Switch with Remote connection in the properties dialog, connecting to Modbus address 40769 (example)
We change switch, switch changes back after the command is sent.
After next poll, switch is back on.

Reasons we believe:
    Modbus is Polled, reads register (40769=0)
    Modbus writes register (40769=1)
    Lookout 40769=0, PLC 40769=1
    Wait for next poll
    Read register, 40769=1
    All happy

We have obeserved the same acticity, so we connected through the Edit Connections instead.  Saves some "explaination" headaches with the client operators.

Mike

[rekholm]

Thanks RKDomer and Mike for your replies..

RKDomer - My pollrate is set to 0:01 seconds! As soon as the remote RTU sends it's status or ACK back to the Controller, within 1 second, my display should change. Immediate Writes are turned on. But you are correct.. It is not actually updating until the next time the site gets poll'd it would seem.

     Toggle as in flip the switch the other way.. from OFF to ON or ON to OFF...

Mike - explain how you "connected through the Edit Connections instead." I don't get that as an option when I right-click on the address in Object Explorer.

[Mike@DTSI]

Right click modbus object, goto Edit Connections.

[rekholm]

"Edit Connections" is  not available.. Only "Edit Data Member Configuration"...