How do i get message on hmi when PLC looses power

Laker31 · Apr 14, 2014

Hi,
I am working on a senior project. I would like to have either an Alarm or a message on the HMI saying that the PLC lost power or the communication was lost between the HMI and the PLC. I have read somewhere I could use the timeout from the HMI. However I do not know how to configure it or where to find it. Please help me.
I use the following equipment:
- AB PanelView Plus 1000
- FactoryTalk View Studion - Machine Edition
- AB Compact Guard Logix L45s
- RSLogix 5000

Thank you,

Plastic · Apr 14, 2014

Ta Da! Task complete

Laker31 said:
Hi,
I am working on a senior project. I would like to have either an Alarm or a message on the HMI saying that the PLC lost power or the communication was lost between the HMI and the PLC. I have read somewhere I could use the timeout from the HMI. However I do not know how to configure it or where to find it. Please help me.
I use the following equipment:
- AB PanelView Plus 1000
- FactoryTalk View Studion - Machine Edition
- AB Compact Guard Logix L45s
- RSLogix 5000

Thank you,

When you panelview displays "Error" in 100% of you objects that have a PLC tag connection...... then you know that the HMI is not connected to the PLC.

Ken Roach · Apr 14, 2014

Welcome to the Forum ! Have the snowbanks melted yet up in the Soo ?

RSLinx Enterprise has a pre-defined Item called "@IsPresent" for each Shortcut. It tells you if the communications path to the controller is running.

You can use it as an Alarm Trigger, or to animate the Visibility of some warning text.

The syntax is just [ShortcutName]@IsPresent

Laker31 · Apr 15, 2014

Ken Roach said:
Welcome to the Forum ! Have the snowbanks melted yet up in the Soo ?

RSLinx Enterprise has a pre-defined Item called "@IsPresent" for each Shortcut. It tells you if the communications path to the controller is running.

You can use it as an Alarm Trigger, or to animate the Visibility of some warning text.

The syntax is just [ShortcutName]@IsPresent

Thank you Ken.

Unfortunately there is still snow bank in the Soo and I was not able to make your advise work. When I write your syntax in the visibility expression for my warning text it tells me that i have an invalid character in the expression.

Here is screen print of it. http://imgur.com/ZCJP6oa

Thanks for your help

Ken Roach · Apr 15, 2014

All you need for the animation expression is:

[TeamLOCI]@IsPresent

Laker31 · Apr 15, 2014

Ken Roach said:
All you need for the animation expression is:

[TeamLOCI]@IsPresent

It still gives me the same issue. Any idea why?

http://imgur.com/aUKifG1

Thanks a lot for your help. This project is killing me.

Geospark · Apr 15, 2014

Ken Roach said:
All you need for the animation expression is:

[TeamLOCI]@IsPresent

Should there be {curly braces} instead of [square] ?...

{TeamLOCI}@IsPresent

G.

Ken Roach · Apr 15, 2014

Shame on me for not checking. The curly brackets go around the whole thing.

I think that's because an RSLinx Enterprise pre-defined Item is more like a Direct Reference than it is like an HMI Tag, because it explicitly includes the Shortcut.

{[TeamLOCI]@IsPresent}

Geospark · Apr 16, 2014

Ahh, I've never used @IsPresent before so I though it was special in that you didn't have to bracket it. Hopefully that works.

G.

Laker31 · Apr 16, 2014

Thank you everyone, the text box appears now.

However, it takes 20 s for the HMI to realize that it lost communication with the PLC controller. Is there anyway to make the HMI reacts faster?

Ken Roach · Apr 16, 2014

I don't think there's a way to configure the timeout.

I think 20 seconds is far too long for a fast network, but it's probably set way down at the TCP/IP stack level and those sort of long timeouts are traditional.

Geospark · Apr 16, 2014

I found this...

43438 - @IsPresent is slow to change when the Ethernet cable is pulled
Access Level: TechConnect

Seems it is configurable Ken?

G.

Ken Roach · Apr 16, 2014

Both RSLinx Classic and RSLinx Enterprise have an @IsPresent pre-defined item.

That technote refers to adjusting the timeout in RSLinx Classic.

As far as I can tell, there is no similar method for adjusting the RSLinx Enterprise drivers that the PanelView Plus uses.

Bit_Bucket_07 · Apr 16, 2014

Why not simply read a square wave heartbeat pulse from the PLC and trigger an alarm via two counters in HMI logic that increment whenever Heartbeat==On or Heartbeat==Off? That would verify not only a good communication link, but that the PLC is actually running.

kopitalk · Apr 16, 2014

I often use variable increment to indicate PLC heartbeat. When it goes to 0, I know there's something wrong either with the PLC or communication in between.

How do i get message on hmi when PLC looses power

Laker31

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Plastic

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Ken Roach

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Laker31

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