Teledyne 1220 - Multipoint flammable gas and vapor detection system - Manual (Page 22)

3 Installation Model 1220
3-4
Teledyne Analytical Instruments
Figure 3-2 Maximum Loop Resistance for Sensor Connection
The terminals marked "Ext. Audible Alarm" provide an external signal
that is activated whenever the audible alarm is activated. By setting jumpers
on the Control Unit PCB (see section 3.3), the external signal can be either
(1) a contact closure, or (2) a powerline level signal.
Reactive loads connected to the relay contacts must be equipped with
appropriate transient suppression networks to prevent spurious triggering of
sensitive alarm circuits.
Analog output from each channel module should be connected to
monitoring equipment as shown in Figure 3-3. Note that the monitoring
equipment inputs should be floating (not grounded). The cable shield should
be connected to ground only at one end of the cable.
Figure 3-3 Analog Output Connection