Eurotherm 394, User Manual

Page: 67 / 142

HA250385
Issue 7 Nov 06
Page 63
MULTIPOINT CIRCULAR-CHART RECORDER: USER GUIDE
5 RELAY OUTPUT OPTION
5.1 INTRODUCTION
The relay output option can have various numbers of relays. A relay board can have two, four or six relays. There can
be one, two or three relay boards mounted within the recorder. Each relay has change-over contacts (i.e. common,
normally closed and normally open). In alarm or power off conditions, the common and normally closed contacts
are closed.
5.1.1 Configuration
Alarm types, thresholds etc. are set up as described in section 4.5.2. Each relevant Process Variable can operate one
or more relays using jobs.
JOBS
A single job 'Drive relay N of card N' (while active/inactive) is added to the job list shown in Section 4.1.5.
5.1.2 Relay specification
The relay specification for resistive loads is given below. Derate with reactive or inductive loads in accordance with
figure 5.1.2, in which:
F1 = Actually measured on representative samples
F2 = Typical values (according to experience)
Contact life = Resistive contact life x Reduction factor.
Number of relays per board two, four or six
Estimated life 30,000,000 operations
Maximum contact voltage 250V ac
Maximum contact current 2 Amps
Maximum switching power 500 VA or 60 W
Safety isolation (dc to 65Hz; BS EN61010) Installation category II, Pollution degree 2 (see page 2 for definitions).
Relay to relay: 300 V RMS or dc (double insulation)
Relay to ground: 300V RMS or dc (basic insulation)
F1
F2
1
0.8 0.6 0.4 0.2
0.3
0.4
0.5
0.6
0.7
0.8
0.9
1
F
Reduction Factor F
Power factor (cos
φ
)
Figure 5.1.2 Derating curves