How to put limits in some parameter and get alarm sound when limit crosses.

[Vaibhav2121]

How to put limits in some parameter monitored in OpenMct and get alarm sound when limit crosses.

[jvigliotta]

Hi @Vaibhav2121 checkout our SinewaveLimitProvider for an example: https://github.com/nasa/openmct/blob/master/example/generator/SinewaveLimitProvider.js

Once you create a provider you can add it using openmct.telemetry.addProvider(provider)

[Vaibhav2121]

hi jivigliotta,
sinewaveLimitProvider provides limit for 1 graph. How can we apply different limits to hundreds of parameter.

[davetsay]

@Vaibhav2121 , you can define which parameters your limit provider applies to in supportsLimits. The example in SinewaveLimitProvider applies to a type, domainObject.type === 'generator'. You can change that to apply to a different type, a set of named parameters, or whatever else.

[Vaibhav2121]

Dear Sir,
I have hundred parameters of one domainObject.type, how can i apply limits to each individual parameter of that type, because if I am applying limits, same limits is applicable to all object.

Example following is dictionary.json

{
"name": "Example Spacecraft",
"key": "sc",
"measurements": [
{
"name": "Fuel",
"key": "prop.fuel",
"values": [
{
"key": "value",
"name": "Value",
"units": "kilograms",
"format": "float",
"min": 0,
"max": 100,
"hints": {
"range": 1
}
},
{
"key": "utc",
"source": "timestamp",
"name": "Timestamp",
"format": "utc",
"hints": {
"domain": 1
}
}
]
},
{
"name": "Thrusters",
"key": "prop.thrusters",
"values": [
{
"key": "value",
"name": "Value",
"format": "enum",
"enumerations": [
{
"string": "ON",
"value": 1
},
{
"string": "OFF",
"value": 0
}
],
"hints": {
"range": 1
}
},
{
"key": "utc",
"source": "timestamp",
"name": "Timestamp",
"format": "utc",
"hints": {
"domain": 1
}
}
]
},
{
"name": "Received",
"key": "comms.recd",
"values": [
{
"key": "value",
"name": "Value",
"units": "bytes",
"format": "integer",
"hints": {
"range": 1
}
},
{
"key": "utc",
"source": "timestamp",
"name": "Timestamp",
"format": "utc",
"hints": {
"domain": 1
}
}
]
},
{
"name": "Sent",
"key": "comms.sent",
"values": [
{
"key": "value",
"name": "Value",
"units": "bytes",
"format": "integer",
"hints": {
"range": 1
}
},
{
"key": "utc",
"source": "timestamp",
"name": "Timestamp",
"format": "utc",
"hints": {
"domain": 1
}
}
]
},
{
"name": "Generator Temperature",
"key": "pwr.temp",
"values": [
{
"key": "value",
"name": "Value",
"units": "℃",
"format": "float",
"hints": {
"range": 1
}
},
{
"key": "utc",
"source": "timestamp",
"name": "Timestamp",
"format": "utc",
"hints": {
"domain": 1
}
}
]
},
{
"name": "Generator Current",
"key": "pwr.c",
"values": [
{
"key": "value",
"name": "Value",
"units": "Amps",
"format": "float",
"hints": {
"range": 1
}
},
{
"key": "utc",
"source": "timestamp",
"name": "Timestamp",
"format": "utc",
"hints": {
"domain": 1
}
}
]
},
{
"name": "Generator Voltage",
"key": "pwr.v",
"values": [
{
"key": "value",
"name": "Value",
"units": "Volts",
"format": "float",
"hints": {
"range": 1
}
},
{
"key": "utc",
"source": "timestamp",
"name": "Timestamp",
"format": "utc",
"hints": {
"domain": 1
}
}
]
}
]
}

Here measurements[values].key is "value" or "utc" . I am applying limits to "value" in sinewavelimitProvider it is becoming common to all parameters. How to apply limits to individual parameters of same object type.

[jvigliotta]

Hey do you have an example of your current implementation? Might help us better understand. Do you want the limit to only relate to that field of the datum?

[Vaibhav2121]

I want to apply different limits to each parameter like different limits to Fuel, Generator temprature, Generator current and Generator voltage. If I apply limits on value the same limits applies to all parameter. how to aplly different limits to different parameters.

[davetsay]

@Vaibhav2121 , you could use a map to apply different limit evaluations to different parameters. Something like below.

YourProvider.prototype.getLimitEvaluator = function (domainObject) {
    // define limits map
    const evaluateFunctions = {
        parameterKey1: (datum, valueMetadata) => {},
        parameterKey2: (datum, valueMetadata) => {},
    };
    
    // use identifier key or identifier namespace/key to get evaluate function from map
    const evaluateFunction = evaluateFunctions[domainObject.identifier.key];
    
    return {
        evaluate: evaluateFunction
    };
}