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Disclaimer: This document is written in the hope that you can utilize for your own education to gain knowledge of PLC systems (should you decide to utilize this document). Although I believe the information in this document to be accurate, it is YOUR responsibility to verify this information before implementing it in any way, especially when damage to personnel or equipment could result. By continuing to read this document, you agree to hold no one who writes, modifies, or distributes this document liable in any way (even negligence). Due to the wide variety of plant applications, some of the examples in this document may be prohibited at your location, or could cause damage to equipment, or harm personnel.

Author: Ricky Bryce (Montgomery County, IL)

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Alarms

Alarms are designed to alert the operator if certain conditions are present such as Low temperature, Low Oil Levels, and various machine failures. The Panelview terminals have a dedicated alarm screen for this purpose. Be sure you are not relying on your Panelview as a primary warning device that could cause damage to personnel, equipment, or cause significant downtime.

Alarm Banner

The alarm banner appears over other screens when an alarm is triggered. To create an alarm banner, right click “Screens” in the application tree.

Once you create your alarm banner screen, go to Screen | Properties and increase the resolution of your screen to 8 x 8 as we did for the pumps screen. This will allow us more precise positioning of objects we place on the alarm banner screen.

Next, Let's Look at the available buttons you can add to this alarm banner. Click Objects | Alarm Buttons from the menu bar. Let's discuss each of these buttons individually:
1. Acknowledge: Marks the alarm as acknowledged that is currently displayed in the alarm banner. The alarm banner will disappear, but this does not clear the alarm condition.
2. Clear: This button makes the banner disappear from your screen. This does not acknowledge the alarm, nor does it clear the alarming condition. You will need to make sure this button exists on the alarm banner to clear the banner if no conditions can be acknowledged.
3. Print: This button will print a single alarm if you have an RS232 printer. (Note: The RS232 port cannot be used for downloading an application if it is configured for printing)
4. Clear Alarm List: Clears the Alarm List and the Alarm Banner even if the alarm condition still exists.
5. Print Alarm List: Prints All the Alarms in the list.
6. Ack All: This button allows the operator to acknowledge all alarms that have not yet been acknowledged. This will cause the alarm banner to disappear from the operator screen, but does not clear the condition that caused the alarm.

Let's move the Clear button over the F1 Button, and add an Acknowledge button to the Alarm banner. We'll place the Acknowledge button over the F2 Button. Modify the inner text of each button to reflect the function key it is associated with as shown:

Let's also add the alarm list object to your screen as shown (Objects | Alarm List), and edit the text object's inner text to read “Alarm Banner”.

You can double click the alarm list to change various properties. For this example, we will just leave them at default.

Now, let's see what options we have available for alarming: In your application tree, open the alarm folder, and go into “Setup”.

In the top portion of our setup, we have various options for the banner and alarm list:

At the bottom, you have various options to configure tags that will allow the PLC to interact with the alarm list:

On the next tab (Alarm Triggers), the user can configure a list of tags which have the ability to trigger an alarm. These alarms can be triggered by the Least Significant bit (LSBIT) to Most significant bit in a priority sequence, a Bit with in a word (BIT), or when a tag reaches a certain Value. Most applications will use only one alarm trigger tag. The value of this tag (or the bits that are set within this tag) will define which message is displayed from the alarm messages tab.

Ack Tag: This is the tag the Panelview writes to the PLC to inform the PLC the tag has been acknowledged
Handshake Tag: The Panelview will toggle a bit in the PLC indicating that it has received the alarm trigger.
Remote Ack Tag: The Panelview toggles a tag in the PLC indicating that it had received a Remote Acknowledge for an alarm trigger.
Remote Ack Handshake: Toggles every time the remote Ack tag changes
Acknowledge All Value: This is the value written to the remote Ack tag when all alarms have been acknowledged for a trigger

Next, let's look at “Alarm Messages” This is where we configure the alarm messages based on a trigger.
1. Text: The message displayed when the alarm is triggered
2. Value: The value or bit of the trigger tag that will cause a particular message to be displayed.
3. Trigger: These are pre-defined on the alarm trigger tab.
4. Ack: Specifies whether or not the alarm text on the alarm banner must be acknowledged
5. Print: If you have an RS232 printer, this box will specify if the alarm condition is to be printed.
6. Display: Specifies whether or not the alarm text is to be displayed in the banner once the alarm has been triggered
7. Background and Foreground: Define colors for the alarm text
8. Text ID: A unique identifier that Panelbuilder32 associates with this text in the project.