Jira New Zealand Limited, PO Box 38, Waimate 7960, South Canterbury, New Zealand.
Head Office 03 689 1374 -  fax: 03 689 1375 - Dunedin 03 742 1145  - Christchurch 03 741 1219
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University of Otago
 
Removing old TC85 master clock controller
Fitting replacement new Tempus clock controller

The University asked us to supply a replacement Master Clock Controller as their old one had broken down and was an obsolete type which could not be repaired.

There are about 800 hundred analogue system slave clocks on Campus in two separate circuits. Both systems are IBM 3-wire protocol but one is at 230VAC and the other is 24V DC

The 24V system is a standard SR2 hourly corrective accumulator system while the 230v system is synchronised by a "short" and a "long" pulse corrective signal at different times of the day.

Both clock types are in common use worldwide and in current production by several overseas manufacturers. Master Controllers to both specifications are readily available and it was decided to replace with a standard Controller of a modern specification.

However, on investigation of the old Master Clock programming it was discovered that the 230V "short pulse" activation had been disabled for some reason. When tests of the clock system were conducted by a computer software test program, it was found that not all clocks responded correctly to the short pulse which pointed to a major service issue on an unknown number of slave clocks. It was decided that the new Controller should avoid the short pulse generation to avoid major disruption of the majority clock system.

This meant we could not supply a standard Controller as these produce all required pulses on demand. However we were able to supply a Tempus P which is highly configurable and able to be programmed to drive both the system clocks to the customer specifications.

In these two pictures alongside, Barry Rowley (Electrical Leading Hand, Property Services at UOO) and Garth from Jira, have removed the old TC85 Master Controller. This was made about 20 years ago by a UK company called Plessey who are no longer active in NZ.

As can be seen in the second picture, the new Tempus Controller has been fitted and is being wired to the correct specification.
Impulse clocks 24VDC data signals relay_reTransmitter MK5M specification analogue clocks multi floor installations

The Clock 24V system depends on relay re-transmitters located in each building on Campus with additional re-transmitters on each floor.

The relay unit here is made by a company called Simplex who were at one time active in NZ.
Tempus_P version master controller programmed to support IBM Simplex system secondary clocks

This picture shows the replacement Tempus controller.

It is fully automated for in the event of power failures and for unattended NZ DST

A special indexing feature permits timekeeping accuracy of better than 2 seconds per year without need for external synchronisation from GPS or NTP etc.
Completed installation Tempus master clock controller to synchronise 230vac 50hz IBM/Simplex 3 wire system slave clocks and MK5M minutes impulse 2 wire 24vdc secondary circuits The finished reinstallation.
Credits due:
University of Otago, Property Division
Clock-o-Matic of Belgium for the Tempus P Controller