iNS/iDS 2-Wire System Manual
350-077
Rev. D - 1/20/2021
Page 18 of 107
3.4
iCCU-S2 Central Control Unit Installation Procedure
Note, all wiring must be completed before applying power to the iCCU-S2.
It is required to connect the LOGIC GROUND wire from CABLE-C-LG or CABLE-
C to the cabinet’s
LOGIC GROUND even when SDLC will not be used. This is because at some point, if the cabinet is
upgraded to use SDLC, it will already be correctly wired and will prevent a future oversite and failure of
the iCCU, traffic controller or other equipment on the SDLC bus. Please note, NEMA TS2 cabinets tend
to have an explicit LOGIC GROUND (NOT TO BE CONFUSED WITH PED COMMON OR OTHER
GROUNDS). This would be the DC logic ground of the power supply that provides DC voltage to the
traffic controller. Connection of this LOGIC GROUND should be the very first step of installation.
3.4.1
Cabinet Interface for Ped Intervals and Ped Calls
The iCCU-S2 is expected to sit on a shelf inside the Traffic Controller cabinet. The iCCU-S2 can function in one of three
configurations:
1. BIU Mode
2. SDLC Hybrid Mode
3. Hard-Wired Mode
1. BIU Mode
The iCCU-S2 can obtain ped interval information and place ped calls via the SDLC bus. For the iCCU-S2 to work in this
mode, the Traffic Controller must support NEMA TS2 compliant SDLC and be communicating with an MMU. Any standard
SDLC cable can be used (such as P/N:
iN2-SDLC-CABLE
) if there is an available port to plug into. If there are no
available ports, a “Y” cable is available (P/N:
iN2-SDLC-YCABLE
) to insert between an existing connection and the
Traffic Controller.
When using SDLC, it is necessary to share a common logic/signal ground with the Traffic Controller and other
devices on the SDLC bus. Therefore, each iCCU-S2 is shipped with CABLE-C-LG. This cable connects to the
connector on the iCCU-
S2 labeled “C/To Ped Inputs”. This cable only has a single wire, which must be connected
to the cabinet’s logic/signal ground. Note, this is different from Earth or chassis ground. Please refer to your
cabinet’s wiring diagram to find the appropriate logic/signal ground connection point.
* Failure to establish this ground connection can result in damage to the iCCU-S2, the Traffic Controller, or other
hardware on the SDLC bus. *
For proper operation and to maintain the product warranty, it must be guaranteed that the iCCU-
S2’s logic/signal
ground is tied to the cabinet’s logic/signal ground.
This mode requires configuration of the Traffic Controller to reserve a detector rack BIU address for the iCCU-S2 as well
as remapping of ped inputs, typically using logic statements. Please consult the Traffic Controller
’s user manual for more
information.
2. SDLC Hybrid Mode
The iCCU-S2 can obtain ped interval information from the SDLC bus while placing calls using traditional wiring to the
cabinet’s ped input. For the iCCU-S2 to work in this mode, the Traffic Controller must support NEMA TS2 compliant SDLC
and be communicating with an MMU. Any standard SDLC cable can be used (such as P/N:
iN2-SDLC-CABLE
) if there is
an available port to plug into. If there are no available ports, a “Y” cable is available (P/N:
iN2-SDLC-YCABLE
) to insert
between an existing connection and the Traffic Controller.
Additionally,
CABLE-C
is required to place calls to the cabinet’s ped inputs. It provides four separate contact closures for
four pedestrian phases. They are identified as A (brown), B (red), C (orange), and D (yellow). Common is black. The wire
