Chapter 10
Relay Contacts and Event Inputs
10.1
Relay Contacts
10.1.1
Introduction
One single set of mechanical SPDT relay contacts are available.
There are two possible relay choices:
Standard Voltage and High DC-Voltage.
10.1.2
Relay Operation
The relay may be configured for programmable pulse
or one of these clock conditions: (1) out-of-lock, (2)
fault, (3) alarm
, (4) stabilized, and (5) failsafe, indicating loss of inlet power. Figure 3.5 illustrates the
rear panel connection. A fault condition connects the normally closed contact (NC) to the common contact
(COM). The normally open contact (NO) operates in a manner opposite to the NC contact.
10.1.3
Standard Voltage Relay Ratings
Specification
Value
Arrangement
1 set of Form C (SPDT) contacts
Contact resistance
100 mΩ
Operate, release time
Approx. 6 ms, 3 ms
Rated voltage
250 Vac (30 Vdc)
Rated switching cur-
rent (resistive)
8 A at 250 Vac, 5 A at 30 Vdc
Max switching capacity
2,000 VA, 150 W
Expected life
50,000 electrical cycles (100,000 typical)
Min. permissible load
10 mA, 5 Vdc
Table 10.1: Specifications
Figure 10.1: Switching Power
1
Consider the pulse frequency and the relay’s life expectancy.
2
See page 24 for definitions on faults and alarms.