20
Teledyne API Model 480L O
3
Monitor User Manual
09419A DCN8342
Table 3-1. Status Output Definitions
Status Output
Normal Operating –
Transistor State
Sensor OK
Active – Connected to ground
Invalid Reading
Inactive - Open resistance
Check Lamp
Inactive - Open resistance
Pneumatic Error
Inactive - Open resistance
3.4.3 HIGH-CURRENT RELAY OUTPUTS
Three form C relay outputs are provided on the interior I/O connectors (Figure 3-4).
The relays are labeled “Sys OK”, “Hi Alarm”, and “Hi-Hi Alarm”
The relays are dry contact type form C (SPDT) relays with Normally Open (NO),
Normally Closed (NC), and Common (COM) contacts. The relays are capable of
switching up to 250 VAC, 5 A each. For maximum contact life, the relays should
only be used to drive resistive loads.
Important
IMPACT ON READINGS OR DATA
Contact life may be dramatically shortened if inductive
loads are driven without any provision for minimizing
high voltage “inductive kick” that can occur.
These relays have slightly different functions depending on whether the monitor is a
single stream (Table 3-2) or multi-stream configuration (Table 3-3).
Table 3-2. Relay Functions for Single Stream Configuration
Relay #
Function
Normal Operating
State
Relay Coils
1
System OK
Closed
Energized
2
Hi Alarm
Open
De-energized
3
Hi-Hi Alarm
Open
De-energized
Table 3-3. Relay Functions for Multi-Stream Configuration
Relay #
Function
Normal
Operating State
1
System OK Diagnostic
Active
2
Global Hi Alarm*
Inactive
3
Global Hi-Hi Alarm*
Inactive
* The state of the global alarm represents all the Hi or Hi-Hi
alarm states OR’d together, i.e., if the Hi alarm for one or more
of the sample streams is activated, then the Global Hi alarm
will be activated.
