Teledyne 4020 – Hydrocarbon analyzer (special version for automatic background gas switching) User Manual
Page 38
Installation Model
4020
Teledyne
Analytical
Instruments
20
Table 3-3: Analog Range ID Output—Example
Range
Voltage Signal
Current Signal
Application
Output (VDC)
Output (mA DC)
Range 1
0.20
6.8
0–1 ppm CH
4
Range 2
0.50
12
0–10 ppm CH
4
Range 3
0.80
16.8
0–100 ppm CH
4
3.3.3.5
A
LARM
R
ELAYS
The six alarm-circuit connector pins connect to the internal alarm
relay contacts. Each set of three pins provides one set of Form C relay
contacts. Each relay has both normally open and normally closed contact
connections. The contact connections are shown in Table 3-4. They are
capable of switching up to 3 amperes at 250 VAC into a resistive load.
An additional relay (formerly AL-2) is used for background gas
selection signals. The connectors are:
Threshold Alarm 1:
Can be configured as high (actuates when
concentration is above threshold), or low (actuates
when concentration is below threshold).
Can be Configured as failsafe or non-failsafe
Can be configured out (defeated).
System Alarm:
Actuates when DC power supplied to circuits is
unacceptable in one or more parameters. Permanently
configured as failsafe and latching. Cannot be defeated.
(Reset by pressing the STANDBY button to remove
power. Then press STANDBY again and any other
button except SYSTEM to resume.
Further detail can be found in Chapter 4, Section 4.5.15.
Background Gas Selection:
(Formerly Alarm 2 Relay)
The state of this relay indicates the currently selected