Ensemble Designs 7160 Serial Digital Protection DA - Manual (Page 12)

www.ensembledesigns.com 7160-12
Model 7160 HD/SD/ASI/310 Protection DA
Status and Alarm Cabling
In addition to full monitoring and access through the control system, the 7160 module provides
contact closure status indications through the 15-pin D Control connector on the corresponding rear
slot of the frame. These connections can drive an alarm system or other external monitoring devices,
including LEDs. Two override GPI Inputs can also be accessed through the connector. Pinouts for the
status monitoring are given in the preceding illustration.
Form C relay contacts provide both NO (Normally Open) and NC (Normally Closed) switching to
indicate fault status of the Primary and Secondary inputs and the protection switch output. Both
the NO and NC contacts are simultaneously available on the Control connector. Each output is
independently strappable to provide Ground, current limited +5V (1k resistor), or a Common which
appears on the D connector.
The three relay contacts provide the following status reporting:
Primary Good or Failed • – indicates Primary input status as Good when NO contact is active
(switched to Common).
Secondary Good or Failed • – indicates Secondary input status as Good when NO contact is
active (switched to Common).
Switch Position • – indicates the position of the protect switch as either Primary or Secondary
selected. The normal position corresponds to the Primary feeding the input.
An individual common is provided to each of the relays. For each of the three status relays there is a
3-position jumper on the module which configures the common signal that will be used by that relay.
The choices are as follows:
COM • – uses the user-provided common signal from the Control connector.
+5 • – provides a +5V signal through a 1k resistor to the relay common.
Gnd • – uses ground as the relay common.
Because both the NO and NC connections are provided, it is possible to have independent status lines
for each of the two states of a status signal. For example, if the jumper is set to +5V, the Primary NO
output will source +5V when the relay is in the normal position (Signal Failed) and the Primary NC
output will source the +5V when the relay is closed (Signal Good). Additionally, in the case of selecting
+5V as the common, the 1k resistor on the module will act as a current limiter, allowing the direct
connection of ordinary LEDs to each of these output pins. A green LED could be connected to the NC
output and a red LED to the NO output. This would provide complete and explicit indication to the
operator as to the signal status.
Also available through the Control connector are two Override GPI inputs that when closed to ground,
will force the switch to either Primary or Secondary. The GPI inputs are edge-triggered on a negative
pulse, or simply a falling edge. These inputs may also be used to switch back to the Primary after a
fault has cleared.