What Is A Class Change Time Clock?
Fase manufacture and distrubute the UK's most configurable and user friendly class change time clocks but what exactly is a class change timer?
Electronic time clocks come in many different types and styles, all of which are designed to serve specific functions or offer certain features.
A class change time clock, also known as a class change timer, school bell timer, or school break timer, is a time clock specifically designed to indicate the start and end of lessons in a school environment, ensuring that classes start and end on time.
We refer to this type of time clock as a class change timer due to its common use in providing class change notifications in schools. However, the technical name for this type of time clock is a '7-Day Pulse Time Clock.'
Below, we will discuss the Fase class change time clocks, their purpose and how to configure these.
1) The basic operating principals of the Fase class change timers
In their most basic operation, our class change time clocks connect and send signals to fire alarm panels. The fire alarm panels are then configured to receive this signal and activate the fire alarm sounders until the signal from the time clock is removed.
The fire panel is then programmed to ring a unquie class change tone via the fire alarm system whilst this signal is present. If connecting to a conventional fire panel, the class change time clock can be programmed to pulse the fire alarm sounders to generate the unique class change signal.
To achieve this, the class change time clock has an on board clean-contact relay, which serves as the connection to the fire alarm panel. Alarm times are set on the time clock, and when the current time matches an alarm time, this relay energises for a programmable time period. Once this time period has expired, the relay will de-energise until the next class change alarm time.
We call the programmable time period 'Ringing Styles,' which can be configured to ring either continuously or to pulse on and off for your required time period.
If you are replacing an old Danfoss Class Change Timer Clock the see Section 5
2) Setting Class Change Alarm Times
Setting class change alarm times could not be easier.
For class change alarms to ring, alarm times need to be added by the engineer or end user. As shown above, this is a simple process of selecting the day being set and then the associated alarm times for that day.
For example, to set class change alarm times for Monday, navigate to 'Mon' and press the tick button. Doing this will then display a new screen that shows any alarms already set to ring on Mondays and allows for them to be edited or new alarm times to be added. Simply navigate to a time slot and press the tick button to show the alarm time being set in the 24hr format. Set the required alarm time then press the tick button and 'Updating Database' will be shown. The class change alarm will now ring at the time set as long at the time clock is set to 'Automatic' mode.
Quite often, the alarms set for Monday are the same for each school day. If this is the case then the 'Copy' feature can be used to save the engineers time. To use this feature, simply set the Monday alarm times then select the 'Copy' option to copy the alarm times which have been set for Monday to all other week days (Mon-Fri) or to all days (Mon-Sun).
3) Setting The Ringing Style
When a class change alarm rings, the on board output relay will energise to signal the class change event. The style and duration of the output relay energising/de-energising can be configured as required and is called the ringing style.
The ringing style option (displayed as 'Ring Style') allows for the output relay to operate as a continuous pulse or to pulse on/off for a set duration and count depending on your requirements.
Continuously - When set to ring continuously, the output relay will energise for the programmed time period on each class change alarm. Once this time period has expired, the relay will de-energise until the next class change alarm.
This 'On Period' can be set between 1 second and 59 seconds and is used when signalling to an addressable fire alarm panel.
Pulsed - When set to pulsed, the output relay will pulse on/off for the duration required. The 'On Pulse' and 'Off Pulse' can be set independently from each other and the number of pulses can be selected.
For example, when the pulse option is selected, the output relay can be programmed to energise for 2 seconds (On-Duration) and then to de-energise for 1 second (Off-Duration) and then to repeat this pattern for 3 times (Count).
Because a new class change alarm may need to ring in the subsequent minute, the combination of the On-Duration, Off-Duration and Counts can not be set for a duration of more than 59 seconds. This option is used when signalling to a conventional fire alarm panel.
4) Can This Not Be Done By The Fire Alarm Panel?
Although some advanced fire alarm panels do offer built-in time clocks, it is generally accepted to be bad practice to programme class change times via the the fire panels built-in time clocks.
Having a separate class change time clock such as one offered by Fase Controls gives total control of the class change system directly to the end-user allowing easy alteration of class change alarm times amongst other settings.
This not only makes life easier for the end user, it removes the need for expensive fire alarm engineer call outs every time a class change alarm time needs altering or when the class change systems needs to be switched off and back on during school holidays etc.
Often, a few engineer visits will cost more then the supply and installation of the class change timer in the 1st place.
The time keeping abilities of many fire alarm panels are not every accurate and could lose up to several minutes per month. Dedicated class change time clocks are very accurate and very rarely require the time correcting.
5) Can I use a Fase Class Change Time Clock To Relplace A Danfoss Class Change Time Clock?
The now redundant Danfoss class change time (part numbers Danfoss 841 and Danfoss 842) were popular class change time clocks but these are no longer manufactured. These time clocks were also badged as Randell or Bellringer.
You have several options if you are replacing an old Danfoss 841 timer and the Fase class change time clocks can be configured to replaced these old Danfoss timers.
The main difference between the Fase and Danfoss timers is that the Fase unit is designed to signal into a fire panel and for the fire alarm panel to signal the class change events. The Danfoss 841 class change timer was designed to switch high load, high voltage sounder or bell circuits which are totally separate from the fire alarm system.
If you need to replace the Danfoss timer with a Fase timer then the high load, high voltage circuits must NOT be connected to the output relay/terminals of the Fase timer. Instead, the on-board output relay must be used to switch a separate/remote relay or contactor. It is this separate relay which must switch the high load/high voltage circuits.
Fase do offer the Fase/100/12/24 dual output relay for this purpose. If a different relay or contactor is to be used then this must be the suppresed and polarised type.
The Fase range of class change time clocks require a 24v power supply. The old Danfoss class change timers required a 230v supply. If you are to replace the Danfoss unit with a Fase unit then a separate 24v PSU must be installed or the 24v supply taken from the fire alarm panel if applicable.