74
Relay Contacts and Event Inputs
9.5
Connecting to the Multimode Relay
When connecting the 1094B multimode relay, do not exceed the ratings and specifications. Fig-
ure 9.1 below illustrates the 5-mm spaced terminals on the connector plug for fastening wiring.
Normal procedure is to strip the wire by one-fourth inch or more; DO NOT tin with solder prior
to attaching to the connector plug. Tighten the set screw clockwise to secure wires.
Figure 9.1: Rear Panel Relay Contact location and Connector Plug
9.5.1
Relay Contact Operation
The information below gives the contact condition for two states: (1) Fault, or Power OFF and,
(2) No Fault. Silkscreen in Figure 9.1 indicates a Faulted or Power OFF condition.
•
Fault, or Power Off – Left to Center pin open (NO), Center to Right pin shorted (NC).
•
No Fault and Power On – Left to Center pin shorted, Center to Right pin open.
9.6
Introduction to Event Inputs
This section should provide more detail on the operation of the event inputs on the 1094B. To
configure the event capture settings, see Section 5.5, Configuring Event Input Jumpers, and Sec-
tion 7.12, Set Event/Deviation.
9.7
Event Timing Inputs
The Model 1094B provides one dual-function event input channel with 1-microsecond resolution
at three possible input connectors: dedicated event input connector, COM1 or COM2. The event
input channel may be used to time an input signal or continuously measure the 1-PPS deviation.
Data for individual recorded events can be recalled using either the Event/Deviation front panel
key or via the RS-232C interface (see Section 10.3.5). Data for each event will be retained until it is
retrieved using one of these two methods. Thus, if no event data points are retrieved or broadcast,
recording will be suspended when the total number of events reaches 300. As soon as data is
retrieved for a recorded event, its address (001 to 300) is made available for data corresponding to
a new incoming event.
9.7.1
Event Timing – Latency
Event data are recorded using a high-speed capture circuit operating with a 96 MHz time-base.
Latency is limited by the interrupt processing speed of the clock’s microcontroller, which in turn
depends on its workload at the time the event is received. Since the workload varies from time
