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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.