Masoneilan SVI II AP Installation and Maintenance ... - GE Energy

Output Switches
Operation and Maintenance
Temperature Sensor
Output Switches
Introduction
A temperature sensor is located in the electronics module and measures ambient
temperature. This measurement is used to provide temperature compensation for the
position and pressure sensors and other internal electronic components. The
temperature is read via the HART communication link to provide a warning of excessive
ambient temperature at the positioner.
The SVI II AP supports two identical contact outputs, SW #1 and SW #2 (Digital Output
switches), that can be logically linked to status bits. The Digital Output switch terminals
are solid state contacts, similar to relay contacts. Each switch requires its own power
source and must be connected to the appropriate connector on the Electronics Module
Terminal Board.
The switches are polarity sensitive and must be connected only to a DC circuit. When
the switch is OPEN the (+) terminal must be electrically positive with respect to the ( –)
terminal. If the (+) terminal is electrically negative with respect to the (–) terminal, then
the switch will conduct. Polarity reversal will not damage the switch, but the switch
will appear to be always ON.
There must be a series load in the circuit to prevent damage to the switch. If the switch
is connected directly across the power source the current will be limited only by
the capacity of the power source and the switch will be damaged.
NOTE
A 1 A, 24 V power source delivers much more than 1 A
short circuit current.
General Configuration Notes
This section discusses the necessary precautions when configuring a system.
V OUT (Open Circuit) = 30 VDC max
I IN (Short Circuit) = 1 A
CAUTION
30 VDC and 1 A cannot exist simultaneously; doing so will
result in failure of the digital output circuit.
Typical Performance
Digital Switch On
V OUT 1 V (This is the saturation voltage of the digital output
element.)
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