Making Alarm I/Os Smarter – Part 3
This series of blog posts highlights some of the more advanced features found in the new Optima NEXUS nano and RIO xR3 Remote Terminal Units (RTU).
The third installment provides a look at the advanced alarm timing capabilities common to both models. The article builds upon some of the topics already introduced in PART 1, and PART 2.
SEVERITY ESCALATION
OVERVIEW
As previously stated, our goal was to offer improved alarm handling flexibility. Towards that end, all RIO xR3, and all NEXUS nano RTU alarm inputs can be programmed:
- with their own unique sets of alarm severities,
- with their own sets of phase timers,
- with their own sets of extended labels, to make alarms more descriptive.
We applied this extended feature set the discrete alarm inputs as well.
Traditionally, discrete inputs (contact inputs) usually only offer two states: open or closed. Depending on the user selection, either one can be defined as the normal/alarm state. Configuring an input as a NORMALLY OPEN type means, the input is open while NORMAL, and closed while in ALARM. Similarly, setting an input as NORMALLY CLOSED means, the input is considered to be in NORMAL state when the contact is closed, and in ALARM when the contact opens:
TYPE
OPEN
CLOSED
Normally Open
NORMAL
ALARM
Normally Closed
ALARM
NORMAL
Consequently, most alarm handling devices on the market today only allow for two severity levels per input:
- NORMAL, and
- a user defined ALARM level.
Many times custom coding is required to extend these capabilities. Especially when an application demands more than flipping between these two basic states.
The Optima Difference
In our new RTUs, we now feature alarm severity level escalation even for discrete contact inputs. This expands the table shown above as follows:
TYPE
OPEN
CLOSED
Normally Open
CRITICAL
MAJOR
MINOR
WARNING
INFO
Normally Closed
CRITICAL
MAJOR
MINOR
WARNING
INFO
The user can decide, individually per I/O, which of these severity levels will be enabled or disabled. Thereby, the utmost flexibility without the need for custom coding/scripting is achieved. The following section will go through setting up all of the parameters, step-by-step.
PARAMETERS
Configuration
This section contains the basic settings to pick and choose the right I/O.
Narrows the focus to the specific set of I/Os to be worked on. Select the HYBRID INPUTS (Rio xR3) or DISCRETE CONTACT INPUTS (NEXUS nano) MODULE when recreating the examples discussed here.
NOTE: Although the RIO xR3 does not have removable I/O modules, the available inputs and outputs have been logically grouped into ‘virtual modules’ to offer a similar programming interface as found on the NEXUS nano.
Define any LABEL to help identify this group of I/Os.
Select the desired I/O from this group of inputs/outputs by choosing the correct I/O INDEX from the drop-down list.
RANGE: 1 up to the maximum number of I/Os available per selected MODULE.
Select the appropriate I/O TYPE from the drop-down list. Some I/Os can be configured to work in multiple modes. Choose the most appropriate one for each application.
NOTE: Some I/O modules only support a single I/O type. In which case the selection is pre-determined and grayed out.
Enter the I/O LABEL to uniquely identify the currently selected I/O. This is the base label of the I/O.
NOTE: BASE LABELS can later be extended with the BASE LABEL EXTENSIONS available at each enabled severity level to further aid in conveying the meaning of a specific alarm notification.
Analog Input Processing
Used to define all the parameters to process the raw analog inputs.
Amplifies small analog signals for better input range coverage. Spreading a small signal over a larger portion of the range available for the input will improve the fidelity and signal resolution. The following hardware GAIN stages are selectable:
1:1
1:2
1:4
1:5
1:8
1:10
NOTE: Higher gain stages also amplify any undesired noise component, which may be inherent in parts of the input signal.
Use the OFFSET parameter to shift the signal input level up or down. Can be used to match the readings obtained with an external meter, gauge or sensor.
The SCALE parameter can be used to amplify or compress an input signal level. It can be either positive or negative.
This is handy when there is a need to invert a signal, or when a larger input signal must be compressed or a small input signal needs to be scaled up.
Where the gain stages only offered fixed positive ratios, the SCALE parameter can be set to any arbitrary value.
Similar to the OFFSET parameter, adding or subtracting a certain BIAS amount from the input allows for shifting the result up or down after the SCALE operation.
As the BIAS is independent of the GAIN or SCALE, the output can be fine tuned with greater accuracy than with the OFFSET alone.
The QUANTIZER ensures that the output adheres to a specified step size.
For example:
- to guarantee that a temperature reading will be output with a step size of 1/8th of a degree, enter .125
- to achieve a percentage step size of 10, enter 10
- to disable the QUANTIZER enter zero.
Use the UPPER LIMIT to ensure that the adjusted analog value never exceeds the selected maximum. Set to +60Vdc by default.
Use the LOWER LIMIT to ensure that the adjusted analog value never dips below the selected minimum. Set to -60Vdc by default.
The OUTPUT FORMAT parameter takes a template string to make sure the readings obtained will be formatted according to the user specified requirements.
Use it to force the addition of the sign, or specify the number of digits to output. Drop the decimals. Add thousand separators. Allows outputting the final result with the desired level of precision.
A user defined UNIT STRING may be added after the final value is output to specify the desired unit.
Examples:
- Vdc
- %
- m/s
- gal/h
- mA
and many more.
Thresholds & Severity
This section is used to define the alarm threshold and alarm severity parameter sets.
Individually controlled ON/OFF CHECK-BOXES. Allows the user fine grained control over each severity level.
Simply remove the check-mark from any severity that will not be required.
Indicates the SEVERITY LEVEL selected for each ‘band’ or range. The MINOR, MAJOR and CRITICAL ranges can be further graded on a scale from 1 to 9.
This allows fine-tuning the three most essential alarm levels. Use the scale from 1 to 9 to either elevate or downgrade one alarm compared to the rest of the I/Os in the same range. Or use the default level 5 if no special grading is required at this point.
The TYPE simply indicates whether the current severity selection is for a NORMAL or an ALARM range.
NOTE: Automatically managed by the RIO xR3 or the NEXUS nano. No user setup required.
With the PHASE PERIOD, the user controls how long each severity level will last, provided the input remains in alarm condition.
If the input stays longer in alarm than the specified PHASE PERIOD, then a level escalation may be allowed to proceed (if enabled).
An alarm message will only be generated if not blocked by other filters, like Adaptive Alarm Suppression or Alarms Throttling.
Select the proper time SCALE for the specified PHASE PERIOD.
The following time scales are available:
- 0 to 1000 milliseconds (in steps of 5 ms)
- 0 to 240 seconds
- 0 to 240 minutes
- 0 to 240 hours.
Use the BASE LABEL EXTENSION to specify a more descriptive label which will be sent along with every alarm notification once the corresponding alarm threshold has been crossed.
NOTE: The extension label will be added to the base label of the I/O. Maximum length: 40 characters.
Example:
BASE LABEL: Main Site Access Door
BASE LABEL EXTENSION: has been open for more than 5 hours
Result:
The following string will be sent as part of each alarm message caused by crossing the selected threshold:
Main Site Access Door has been open for more than 5 hours
Options
Contains optional settings. This blog post only highlights a small subset. Many more options exist and can be enabled for added functionality.
Enable the PROGRESSIVE / WITH SNAP-BACK option to turn on alarm severity escalation.
Once activated, the length of time an input stays in alarm may be used to escalate the alarm severity.
The user can pick any of the available ranges to be included or skipped as required. The user controls the speed in which each of the stages will be handled by specifying an appropriate duration using the PHASE PERIOD parameter.
Use the SNAP-BACK radio button to influence how the I/O will return to normal once the alarm condition has ended:
Without SNAP-BACK, the input will progressively fall through each of the defined severity levels, just in reverse compared to the order in which they were taken when the alarm was active.
With SNAP-BACK enabled, the input will immediately return to NORMAL once the alarm phase has ended.
QUICK TRIGGER mode: I/O transition is reported immediately upon crossing of threshold. The Qualification Period starts after the transition report has been issued and will be allowed to complete before new transitions will be accepted.
EXAMPLE
This example demonstrates how to add some advanced functionality to one of the most common inputs: the door contact.
Preparation
- Navigate to the I/O MANAGEMENT entry in the main MENU (on the left hand side of the screen).
- Select the CONFIGURATION tab.
- Choose HYBRID INPUTS from the MODULE drop down.
- Select a suitable spare I/O using the I/O INDEX drop-down selector (3 in this example).
- Set the I/O TYPE to NORMALLY CLOSED.
- Enter “Main Access Door” or a similar text as the I/O LABEL.
Your screen should now look similar to this:
Defining the Input
Select the THRESHOLDS tab. Then configure each of the parameters as follows:
QUALIFICATION PERIOD:
UPPER LIMIT:
LOWER LIMIT:
ALARMS THRESHOLD:
HYSTERESIS:
UNIT STRING:
250ms
24
0
8
2
Vdc
Your screen should now look similar to this:
Result:
So far we set up the selected input as a discrete contact input, normally closed. The above listed settings together with a standard door contact wiring ensures that:
- while the (door) contact is closed, the signal level will be pulled to ground, and
- when the door is opened, the contact opens and the input biasing will pull the signal level up to +24Vdc.
The selected alarm threshold and hysteresis will have the following effect:
- while in NORMAL, the input will transition to the ALARM condition as soon as the signal level rises above the alarm threshold of 8Vdc.
- it will only return to the NORMAL condition when the signal level falls below 6Vdc.
This is just one way of configuring the input. Many other variations are possible. Using a qualification timer of 250ms and a hysteresis of 2Vdc will help keeping the input from ‘flapping’ in case the signal level would ever hover close to the selected alarm threshold.
Setting Up The Severity Levels
On the THRESHOLDS tab, enable each of the severity levels and configure them as follows:
| CRITICAL LEVEL: | CRITICAL7 | – | open for >8h. Dispatch tech. |
| MAJOR LEVEL: | MAJOR6 | 3 h | open for >5h. Notify tech. |
| MINOR LEVEL: | MINOR5 | 3 h | open for more than 2h. |
| WARNING LEVEL: | – | 1 h | has been ajar for more than 1h. |
| INFO LEVEL: | – | 1 h | is open. |
| NORMAL LEVEL: | – | – | is closed. |
Your screen should now look similar to this:
RESULT:
The selected PHASE PERIODS will help stagger the different severity levels in case the door contact remains in alarm for the ever longer periods of time. If the door is only opened briefly, the unit will send out one INFO notification once the door opens, and a NORMAL notification when the door closes again.
Should the door remain open for more than one hour, then the WARNING notification will be generated.
If the door is still open after 2 hours, then the MINOR alarm notification will be sent out.
After 5 hours (1h + 1h + 3h) the MAJOR alarm notification will be generated.
And finally after 8 hours (1h + 1h + 3h + 3h) the CRITICAL alarm notification will be sent out.
No further alarm messages will be sent out after that.
If the door closes at any time, the input will immediately transition back to NORMAL (due to selecting the PROGRESSIVE + SNAP-BACK option).
Here are the labels (consisting of the BASE LABEL + BASE LABEL EXTENSION) which will be sent along with each notification:
| BASE LABEL: | Main Access Door | |
| NORMAL: | Main Access Door | is closed. |
| INFO: | Main Access Door | is open. |
| WARNING: | Main Access Door | has been ajar for more than 1h. |
| MINOR: | Main Access Door | open for more than 2h. |
| MAJOR: | Main Access Door | open for >5h. Notify tech. |
| CRITICAL: | Main Access Door | open for >8h. Dispatch tech. |
Proper configuration can also be verified by checking the resulting graph, which updates in real time with any user edits being carried out:
Note that the graph lists the timestamps on the right hand side. They are a handy tool to verify when each event will take place.
SUMMARY
The flexibility offered by the NEXUS nano and RIO xR3 analog inputs processing stages allow even complex operations to be carried out on an input signal without the usual need for custom coding or scripting. The example above clearly highlights the power of the available parametric interface. The web-based Optima GUI turns even advanced setups with escalating severity settings into straightforward point-and-click operations.
OUTLOOK
The upcoming 4th installment in this series will focus on more of the advanced analog input processing capabilities found in the RIO xR3 and NEXUS nano. Stay tuned.
Ralf Doewich
Optima Tele.com, Inc.