SIS Quad

PACS Services offer the SIS Quad system for signals requiring a passive safety system, we will use a junction layout drawing to calculate the equipment required. We will then provide a costed calculation. If the system is purchased the signal company will provide a free issue cabinet (MEC) in which we will install the equipment.

Once installed the SIS system will disconnect all wiring to a signal pole if an impact occurs, including the impact sensor. Once installed it also offers the ability to isolate a single pole completely for maintenance works, where once the whole junction would be turned off.

Below is a typical traffic signal schematic, it shows the number of signal poles, controller location and MEC location. It also shows the equipment on each pole which will enable us to build a quote. The symbols used are more or less standard across the signal industry.

The sheet below is simple/sample calculation for the site above, in this instance we have used a Swarco calculator, we also have calculators for Yunex and telent equipment. Here we add all of the equipment details to determine the correct equipment for each pole. The SIS system is pole based rather than phase based. Once we have populated the calculator with all of the junction/crossing details we can work out the number of isolators and SIS equipment required. We will also add notes below to clarify any assumptions we have made and the drawing reference and revision number the calculation is based upon. This will enable us to then provide a system cost.

MEC Cabinet Images

Here are two images of typical SIS equipment cabinets, we can get approximately 60 isolators in a cabinet as per the cabinet on the left, using all three sides. In certain cases a site will require two MEC cabinets, we will advise this in the notes when the calculator is completed.