CHESTER Input

This article describes the core functionality, hardware description, default configuration, and example JSON messages for the catalog application CHESTER Input.

danger

When upgrading firmware from v1.x.x to version v2.0.0 and newer - it is necessary to backup configuration.

caution

Some basics are not provided, as they are common for all the CHESTER catalog applications. For example, see the article Platform Management on how to work with the interactive console.

Application Overview

The application CHESTER Input is used to measure and observe analog and digital inputs. The sampled analog values are aggregated, the aggregate measurements are buffered, and scheduled for later data transfer in the form of buffered data altogether with the timestamp annotations. Also, the changes on digital input (type trigger) can be tracked with the type of change and timestamp. The buffering strategy allows a higher number of events to be recorded while conserving data bandwidth and power required for data transfer.

CHESTER Input has these four inputs:

Type	Channel	Terminal	Input type	Input range	Typical use-case
Trigger	CH1	A2	Digital - NPN/PNP	0 to 28 V	Switch, button, relay, PLC sensor
Counter	CH2	A4	Digital - NPN/PNP	0 to 28 V	Energy meter pulse outputs (e.g., S0)
Voltage	CH3	A5	Analog - voltage	0 to 28 V	Various voltage transmitters
Current	CH4	A7	Analog - current	0 to 24 mA	Various current transmitters

All these inputs and their options are explained in more detail in the article Input Parameters and Behavior.

Application Variants

CHESTER Input can be ordered in one of these variants:

CHESTER Input

The catalog CHESTER Input hardware consists of the following ordering codes:

• CHESTER-M-BCGLS - Standard mainboard

• CHESTER-X0B:A - Input module (4 channels)

See Ordering Codes for more details.

Firmware build shield options: ctr_ds18b20 ctr_lte ctr_x0_a

CHESTER Input Z

The catalog CHESTER Input Z hardware consists of the following ordering codes:

• CHESTER-M-CGLS - Standard mainboard

• CHESTER-X0B:A - Input module (4 channels)

• CHESTER-Z1 - Backup module

See Ordering Codes for more details.

Firmware build shield options: ctr_ds18b20 ctr_lte ctr_x0_a ctr_z

CHESTER Input ZH

CHESTER Input ZH with external temperature and hygrometer.

• CHESTER-M-CGLS - Standard mainboard

• CHESTER-X0B:A - Input module (4 channels)

• CHESTER-Z1 - Backup module

• CHESTER-S2 - External hygrometer

See Ordering Codes for more details.

Firmware build shield options: ctr_ds18b20 ctr_lte ctr_x0_a ctr_z ctr_s2

Input Parameters and Behavior

For the wiring diagram to CHESTER Input, please follow the terminal block description of the CHESTER-X0 extension module. The extension module CHESTER-X0 is installed in the left slot A, so you have to use the corresponding terminals A1 to A8.

Trigger

The trigger input can be connected to a PLC/sensor output (NPN/PNP), push button, switch, relay, etc. The behavior of the trigger input is configurable.

• When the input changes, the timestamp of the change event is stored altogether with the active/inactive state, this information is buffered, and the buffer of the events is sent (at the latest) with the regular report (parameter interval-report).

• Optionally, input changes to the active (parameter trigger-report-active) or inactive (parameter trigger-report-inactive) states can be reported immediately or with a configurable delay (parameter event-report-delay) to allow capturing multiple consequent input changes.

• Both NPN and PNP input logic types are supported (parameter trigger-input-type).

• The minimum level duration is configured separately for active (parameter trigger-duration-active) and inactive (parameter trigger-duration-inactive) states.

• The maximum number of reports per hour is configurable (parameter event-report-rate). The event throttling limits communication bandwidth and preserves the battery lifespan.

Counter

The counter input can be connected to a PLC/sensor output (NPN/PNP), push button, switch, relay, etc. This input counts the total number of pulses in time.

• The counter value is aggregated periodically (parameter counter-interval-aggreg), and the buffer of aggregated measurements is reported in a configurable interval (parameter interval-report).

• Both NPN and PNP type of input logic is supported (parameter counter-input-type).

• The minimum level duration is configured separately for active (parameter counter-duration-active) and inactive (parameter counter-duration-inactive) states.

Voltage

The voltage input measures the voltage in the range from 0-28 V (overlaps the 0-10 V standard).

• The voltage readings are sampled periodically (parameter analog-interval-sample). These readings are stored as a buffer of samples.

• The collected samples are aggregated periodically (parameter analog-interval-aggreg). The minimum, maximum, average, and median aggregates are computed from the buffered samples. These aggregated results are referred to as measurements.

• Each measurement has an associated timestamp. The buffer measurements are transferred as time-series data regularly (parameter interval-report).

Current

This input measures the analog current in the range from 0-24 mA (overlaps the 4-20 mA standard).

• The current readings are sampled periodically (parameter analog-interval-sample). These readings are stored as a buffer of samples.

• The collected samples are aggregated periodically (parameter analog-interval-aggreg). The minimum, maximum, average, and median aggregates are computed from the buffered samples. These aggregated results are referred to as measurements.

• Each measurement has an associated timestamp. The buffer measurements are transferred as time-series data regularly (parameter interval-report).

Backup

CHESTER Input Z (equipped with CHESTER-Z1) can also report information on the backup battery and external DC power state.

• The current battery voltage and external DC voltage are sent in every report.

• When the DC power input changes, the timestamp of the change event is stored altogether with the connected/disconnected state, this information is buffered, and the buffer of the events is sent (at the latest) with the regular report (parameter interval-report).

• Optionally, DC power input changes to the connected (parameter backup-report-connected) or disconnected (parameter backup-report-disconnected) states can be reported immediately or with a configurable delay (parameter event-report-delay) to allow capturing multiple consequent input changes.

• The maximum number of reports per hour is configurable (parameter event-report-rate). The event throttling limits communication bandwidth and preserves the battery lifespan.

Hygrometer

The optional hygrometer in the CHESTER Input application represents an external temperature and humidity sensor.

• The readings are sampled regularly (parameter hygro-interval-sample). These readings are stored as a buffer of samples.

• The collected samples are aggregated periodically (parameter hygro-interval-aggreg). The minimum, maximum, average, and median aggregates are computed from the buffered samples. These aggregated results are referred to as measurements.

• Each measurement has an associated timestamp. The buffer measurements are transferred as time-series data regularly (parameter interval-report).

Default Configuration

This is the default configuration (printed using the app config show command):

app config interval-report 1800
app config event-report-delay 5
app config event-report-rate 30
app config backup-report-connected false
app config backup-report-disconnected false
app config trigger-input-type npn
app config trigger-duration-active 100
app config trigger-duration-inactive 100
app config trigger-cooldown-time 10
app config trigger-report-active false
app config trigger-report-inactive false
app config counter-interval-aggreg 300
app config counter-input-type npn
app config counter-duration-active 2
app config counter-duration-inactive 2
app config counter-cooldown-time 10
app config analog-interval-sample 60
app config analog-interval-aggreg 300
app config hygro-interval-sample 60
app config hygro-interval-aggreg 300

Specific Commands

info

You can easily explore the whole command tree structure - start with the help command.

Use this command to set report interval (in seconds):

app config interval-report <value>

Use this command to configure a short delay (in seconds) between the trigger or backup event and its reporting:

app config event-report-delay <value>

tip

This feature is useful in systems where another change may arrive shortly after the first one.

Use this command to limit the number of asynchronous trigger or backup event reports in a one-hour window:

app config event-report-rate <value>

tip

This feature helps to conserve power in the battery-operated device and optimizes the amount of transferred data. The regular (periodic) reports set by the parameter interval-report are not counted to this limit.

Use these commands to enable/disable reporting of the backup module power input connect/disconnect events:

app config backup-report-connected false
app config backup-report-disconnected false

Use these commands to set the input type for trigger and counter inputs. The valid values are npn or pnp:

app config trigger-input-type <npn/pnp>
app config counter-input-type <npn/pnp>

Use these commands to enable/disable trigger input to immediately report a change to active or inactive levels:

app config trigger-report-active <true/false>
app config trigger-report-inactive <true/false>

Use these commands to set the active and inactive time duration (in milliseconds) for the trigger and counter digital inputs:

app config trigger-duration-active <value>
app config trigger-duration-inactive <value>
app config trigger-cooldown-time <value>

app config counter-duration-active <value>
app config counter-duration-inactive <value>
app config counter-cooldown-time <value>

info

• The parameter duration-active sets the millisecond delay between the input signal changes to an active level (based on npn or pnp configuration) and when CHESTER reacts to this change. This could be used to filter (debounce) input signal in case the input signal is connected to a "electrically noisy" mechanical switch or relay. It could also be used if the CHESTER has to react to longer pulses than the set duration.
• The parameter duration-inactive is the same as for the duration-active above, except it sets the time for the opposite edge.
• The parameter cooldown-time is a delay protecting CHESTER from too many incoming interrupt events. If a too-fast signal (>10 kHz) is connected, the interrupt handler could consume all the processor time, stopping the execution of other threads. This parameter sets a small delay between executing the interrupt handler again. A default value of 10 ms could be used here.

Use these commands to set the sample and aggregate intervals (in seconds) for voltage / current measurements:

app config analog-interval-sample <value>
app config analog-interval-aggreg <value>

Use these commands to set the sample and aggregate intervals (in seconds) for the optional hygrometer (the accessory CHESTER-S2):

app config hygro-interval-sample <value>
app config hygro-interval-aggreg <value>

Firmware

danger

When upgrading firmware from v1.x.x to version v2.0.0 and newer - it is necessary to backup configuration.

The latest firmware is available in Catalog Applications Firmware chapter.

Example JSON Message

{
  "message": {
    "version": 1,
    "sequence": 7,
    "timestamp": 1670580791
  },
  "attribute": {
    "vendor_name": "HARDWARIO",
    "product_name": "CHESTER-M",
    "hw_variant": "CDGLS",
    "hw_revision": "R3.2",
    "fw_name": "CHESTER Input",
    "fw_version": "v1.0.0",
    "serial_number": "2159018247"
  },
  "system": {
    "uptime": 2058,
    "voltage_rest": 3.74,
    "voltage_load": 3.65,
    "current_load": 36
  },
  "backup": {
    "line_voltage": 24.21,
    "batt_voltage": 3.41,
    "state": "connected",
    "events": [
      {
        "timestamp": 1670580549,
        "type": "disconnected"
      },
      {
        "timestamp": 1670580552,
        "type": "connected"
      }
    ]
  },
  "network": {
    "imei": 351358815178303,
    "imsi": 901288003957939,
    "parameter": {
      "eest": 7,
      "ecl": 0,
      "rsrp": -90,
      "rsrq": -8,
      "snr": 9,
      "plmn": 23003,
      "cid": 939040,
      "band": 20,
      "earfcn": 6447
    }
  },
  "thermometer": {
    "temperature": 23.06
  },
  "accelerometer": {
    "acceleration_x": 0.07,
    "acceleration_y": 0.38,
    "acceleration_z": 9.88,
    "orientation": 2
  },
  "trigger": {
    "state": "inactive",
    "events": [
      {
        "timestamp": 1670580550,
        "type": "activated"
      },
      {
        "timestamp": 1670580553,
        "type": "deactivated"
      },
      {
        "timestamp": 1670580631,
        "type": "activated"
      },
      {
        "timestamp": 1670580634,
        "type": "deactivated"
      }
    ]
  },
  "counter": {
    "value": 12586,
    "measurements": [
      {
        "timestamp": 1670580548,
        "value": 12526
      },
      {
        "timestamp": 1670580698,
        "value": 12583
      }
    ]
  },
  "voltage": {
    "measurements": [
      {
        "timestamp": 1670580548,
        "min": 11.27,
        "max": 11.35,
        "avg": 11.31,
        "mdn": 11.35
      },
      {
        "timestamp": 1670580698,
        "min": 11.26,
        "max": 11.35,
        "avg": 11.29,
        "mdn": 11.27
      }
    ]
  },
  "current": {
    "measurements": [
      {
        "timestamp": 1670580548,
        "min": 10.55,
        "max": 10.91,
        "avg": 10.73,
        "mdn": 10.91
      },
      {
        "timestamp": 1670580698,
        "min": 10.51,
        "max": 10.91,
        "avg": 10.66,
        "mdn": 10.55
      }
    ]
  },
  "hygrometer": {
    "temperature": {
      "measurements": [
        {
          "timestamp": 1670580548,
          "min": 22.99,
          "max": 23.02,
          "avg": 23.01,
          "mdn": 23.02
        },
        {
          "timestamp": 1670580698,
          "min": 23.02,
          "max": 23.08,
          "avg": 23.05,
          "mdn": 23.06
        }
      ]
    },
    "humidity": {
      "measurements": [
        {
          "timestamp": 1670580548,
          "min": 49.66,
          "max": 49.74,
          "avg": 49.7,
          "mdn": 49.74
        },
        {
          "timestamp": 1670580698,
          "min": 49.62,
          "max": 50.07,
          "avg": 49.84,
          "mdn": 49.82
        }
      ]
    }
  }
}