Specifications

December 2008 Page 17–9
Chapter 17. Pilot Wire Interface (HCB/SPD) Module
17
18 on the HCB relay to connection P2-7. Note
that the three-terminal rear interface module
spans four chassis slots and has two terminal
blocks (P1 and P2).
For a three-terminal application, connect the
wire from pin 19 on the HCB relay to connec-
tion P2-8 (the terminal block on the right) on
the Pilot Wire Interface Module’s rear
interface module and the wire from pin 18 on
the HCB relay to connection P2-7.
5. Connect the module’s rear interface
module to the FOCUS chassis.
After connecting all wires, attach the
module’s rear interface module to the rear of
the FOCUS chassis so that it connects to the
Pilot Wire Interface Module or, for a “three-
terminal” interface, to the two modules. Make
sure you install the rear interface module(s)
on the rear of the chassis in the same slot(s) as
the Pilot Wire Interface Module(s).
17.3.2 Software Settings
Once you have completed the hardware installa-
tion and connections, you can configure the Pilot
Wire Interface Module using the FOCUS
Configuration Software (FCS). The default
configuration settings for the module are:
DTT Input/Output = Enabled
DTT Output Trip Hold Time = 0ms. (None)
LOPC Mode = BLK-Short pilot wire
LOCC Mode = BLK-Short pilot wire
DTTC Mode = BLK-Received DTT will short wire
For instructions on configuring the Pilot Wire
Interface Module, please refer to the FCS online
help facility (Configuring the FOCUS Channel
Modules > Current Differential Interface Module
(HCB/SPD)…).
When you connect the module to an existing
HCB/HCB-1 application, you will see a
ground on one of the pilot wire leads
somewhere between the relay and the old
insulating transformer. This ground must be
removed. The appropriate ground connec-
tion is already made inside the FOCUS rear
interface module on the rear of the chassis.
NOTE
Signal Delay < 450 µs – two FOCUS chassis back-to-back
Channel Loss Three Optional Settings:
1) Block Trip (Local)
2) Allows Trip as Overcurrent Relay (Local & Remote)
3) Allows Local Overcurrent Trip and Block Remote
Ter m inal Trip
Pilot Wire Output Maximum 15 V peak
Maximum 100 ma
Direct Transfer Trip Keying input: 48 to 250Vdc at 5 ma
Trip Output: Solid State switch with 1A output at 48 to
250Vdc.
Trip Time: 5ms Solid State Output
Alarm Output Form A alarm contact output rated at 48 to 250Vdc at 1 A
Table 17–1. Pilot Wire Interface Modules (HCB/SPD) Specifications