Universal AC Controller – System Infra Solutions

Universal AC Controller

Universal AC Controller

SISPL AC controller is an integrated multifunction high speed micro controller based System. It is a comprehensive solution for managing a two number of ACs intelligently at a typical telecom site. This system has been designed as per specifications issued by BSNL. The AC Controller is suitable for Window ACs / Split ACs / Heat Sensible ACs. In these system AC units is start/stop based on sensing of shelter temperature through a single real time temperature sensor (having accuracy of 0.5 oC). AC units is based on room temperature and both the ACs have settable temperature differential for starting and stopping of the units. In case of power failure, the controller have sufficient memory for that original sequencing of running of AC units have maintained. In this system proved the facility of sequential and equal run hour maintain. This system includes protection of under/over voltage & load current.

System feature:

  • Status monitoring
  • Current drawn
  • Maintain equal run hour
  • Sequential running
  • High & Low Voltage Protection.
  • Over & under load protection.


Monitored Parameters

1> Analog parameter

  1. Mains voltage.
  2. AC Load Current.
  3. Room Temperature.
  4. AC Run hours.

2> Digital parameter

  1. Mains Fail.
  2. AC Fault.
  3. High room temperature.
  4. AC Overload/under load.

Configuration (programmable parameters)

The configuration for controller module is as follows.

S.NO Parameter Name Max Value Min Value Default Value
1 Mains High Cut off 350 70 485 Volt
2 Mains Low Cut off 250 50 240 Volt
3 AC on temperature 80 10 35 °C
4 AC off temperature Below5 degree of AC on temperature 10 22 °C
5 2nd AC on time 100 1 5 Minute
6 AC Current status Enable/disable Enable Disable Enable
7 AC Current overload 40 1 20
8 AC Current under load 15 1 3
9 High Room temperature 80 10 40 °C
10 Current Ratio 250 25 125
11 AC run hour 10 1 3 Hours


Calibration Parameter

The calibration parameters are as follows.

S. No Parameter name Actual value Measured value
1 Main Voltage XXX XXX
2 AC#1 Load current XX.X XX.X
3 AC#2 Load current XX.X XX.X
4 Room Temperature XX.X XX.X

Actual values display what have you apply and measured value is measurement by controller.


Thee operation of pace controller is given below.

  • Key function
  • Calibrations
  • Configurations
  • System operations
  • Alarm indication

Key Function

There are three switches in Display Board


This switch is used for increment in configuration & calibration.


This switch is used for two purposes one for decrement and other for display scrolling. Normally this switch is working for display scrolling. When you go for configuration that time this switch working for decrement.


This is the ENTER key its work on defined the configuration and calibration.


For any analog parameter calibration you can go for calibration mode by configuration. In calibration mode you can go for that parameter which you want to calibrate. After you can set the value by increment and decrement key if actual value is equal to apply value press enter key and then press the escape key. And check that parameter is ok or not.

In mains voltage, AC#1 Load current, AC#2 Load current & Room Temperature.


For any programmable parameter changing you can go in menu setting by configuration mode. In configuration mode you can go for that parameter which you want to change after this you can adjust by increment and decrement key and then press enter key. Then go for escape.

System Operation

The operation of ac controller is working on presence of mains supply. When mains is available and room temperature is higher than ac on temperature. This controller is providing the facility of sequential and equal run hour maintain. Some time both ac is working as per requirement (High room temperature).

If first AC is on and room temperature is not maintained within 30 minute then second ac is on. When both ac is working and room temperature is down  to ac off temperature then that ac is off who started first, After five minute  again check the room temperature and if room temperature is down that 2nd ac is also off.

Other condition of ac operation when room temperature is  higher than ac on temperature that time that ac on whose run hour is below than  other ac run hour. And maintain the room temperature, if room temperature is below than ac off temperature ac is off. When again room temperature is higher than ac on temperature that time 2nd ac is on.

Alarm checking

  • Mains fail

if mains is not coming within range mains fail alarm is  raise. When mains is available within range this mains fail alarm is clear.

  • AC Fault

When AC is switch on and wait five minute if AC current status is enable and  AC is not draw any current or draw more current as per set limit that time AC is switch off and raise the AC faulty alarm.

  • High room temperature

If the room temperature is higher than the set limit of room temperature high alarm that high room temperature is raise and clear whan room temperature is below than 2degree of set limit.

Connection Diagram

Front View

Back view