MadgeTech Event 101, Event 110 Application Note

Application Note

State, Event, and Pulse Data Recorders

Choosing Between a State, Event, or Pulse Recorder

The State, Event, and Pulse recorders, although related, each serve very different purposes in
meeting the needs of a specific application.

A State Recorder indicates how long an event lasts.

An Event Recorder indicates when an event occurs.

A Pulse Recorder indicates the number of times an event
occurred in a given time interval.

This application note will discuss the differences between these three types of units and provide
some insight into practical applications to help the user choose the correct product for their
application

State Recorder

The State Recorder records a time-stamped value whenever the state of the signal changes over a
period of time. This is useful when the user needs to be able to collect data on an event duration.

EXAMPLE:

If the user is monitoring traffic through a door, the State Recorder would take a data point:

MadgeTech, Inc.
[phone] Phone
[phone] Fax
www.madgetech.com
[e-mail]

879 Maple Street,
Contoocook, NH 03229

1. When the door opens

2. When the door closes

The State Recorder records the data points to indicate how long a door was open; that is, the
data collected tells the user that a change in the “state” of the door occurred:

1. When the door opened at 9:30:00 am

2. When the door closed at 9:30:05 am

The user can then calculate that the door was open for a period of 5 seconds.

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Application Note

However it should be noted that if the leading edge of a state occurs between position 0 and
position 1, it will be recorded as taking place at position 1.

The State Recorder samples the state of the input at fixed intervals. In order for a state change to
be recorded, the change must be present at the time it is sampled. If more than one transition
occurs between position 0 and position 1, only the state of the input at the time of the sample
will be recorded. Therefore, the sample period must be set to less than the minimum time
required for the input signal to rise and fall. If the change in state does not persist long enough to
be active at the time of sampling, it will be missed.

EXAMPLE:

If it takes 30 seconds for a garage door to open and close, the time period should be set to
less than 30 seconds to ensure the state change is not missed

MadgeTech, Inc.
[phone] Phone
[phone] Fax
www.madgetech.com
[e-mail]

879 Maple Street,
Contoocook, NH 03229

Another example of an application for the State Recorder is the monitoring of a furnace or pump
turning on and off, both of which have a long enough state change to be captured by the State
Recorder.

Event Recorder

The Event Recorder records a single direction time-stamped data point when an event takes place
within a fixed reading interval. This is useful when the user needs to be able to collect data on
when an event occurred, but does not need to know the duration of the event.

EXAMPLE:

If the user is monitoring the traffic flow through a door, the Event Recorder will take a data
point recording:

1. That the door opened, and

2. That the door opened again, and

3. That the door opened again.

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Application Note

Unlike the State Recorder, the Event Recorder does not provide the data points that would indicate
how long the door was open. The Event Recorder can track the number of times the door was
opened, but not how long it was open for.

EXAMPLE:

Data from the Event Recorder tells the User that events occurred:

1. When the door opened at 9:30:00 am, and

2. When the door opened at 9:37:04 am, and

3. When the door opened again at 12:22:13 pm

Thus, the user can track the number of times the door was opened, but not how long the door
was open each time.

The Event Recorder has a resolution of 1 second. This means that the device has the ability to
record an event every second. Unlike the State Recorder, the Event Recorder does not require a
persistent signal. The Event Recorder will trigger on the leading edge of the signal transition.
However, it should be noted that:

If a data point occurs between position 0 and position 1, it will be recorded as having taken place at position 1.

MadgeTech, Inc.
[phone] Phone
[phone] Fax
www.madgetech.com
[e-mail]

879 Maple Street,
Contoocook, NH 03229

If more than one data point occurs between position 0 and position 1, only a single data point will be recorded.

Another common application for an Event Recorder is monitoring tipping-bucket rain gauges. The
Event Recorder will record data when the bucket tips and the contact is closed. It is unlikely that
the bucket on the rain gauge will tip more than once per second, therefore the Event Recorder will
not miss recording any data points.

Pulse Recorder

The Pulse Recorder records the number of pulses that happen over a period of time. Unlike the
State or Event Recorder, the device does not time-stamp each pulse, but rather groups together or
bins the number of pulses according to the time period they occurred in.

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Application Note

EXAMPLE:

If the user is monitoring traffic through a door, the Pulse Recorder will log the number of times
the door was opened during each interval:

1. The door was opened 3 times between 9:30 and 9:31 am

2. The door was opened once between 9:32 and 9:33 am

3. The door opened twice between 9:36 and 9:37 pm

9:30 9:40

The Pulse recorder requires a signal of at least a 10 microsecond duration and at least 20
microseconds between the leading edge of each pulse to be counted. If these conditions are met,
then every pulse will be logged, with up to nearly 4.3 million pulses per time interval.

Conversely, a pulse may not be recorded if it is less than 10 microseconds or if more than one
pulse occurs within a 20 microsecond period. If the latter happens, further data points may not be
recorded until 20 microseconds after the first pulse.

MadgeTech, Inc.
[phone] Phone
[phone] Fax
www.madgetech.com
[e-mail]

879 Maple Street,
Contoocook, NH 03229

A common application for the Pulse Recorder is to measure the flow rate or total volume of a
pipeline. The Pulse Recorder collects pulses generated by a flow meter and uses that information to
calculate the number of gallons per minute. The flow meter produces a pulse that is too rapid to
be collected by the Event or State, yet can easily be binned by the Pulse Recorder. The important
data here is not the exact time when the pulse took place, but rather the number or pulses in a
time interval.

If you have any further questions about your application, please contact MadgeTech Customer
Support at 603.456.2011, or via e-mail: [e-mail]

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