SPS 4001B
Instruction Manual
Calibration Gas Solenoids
The solenoids sequence the calibration gases. One solenoid controls calibration gas 1 (high calibration gas), and the other controls calibration gas 2 (low calibration gas). The solenoids activate and deactivate to allow the calibration gases to flow between the sequencer and Oxymitter 4000.
Pressure Switch
The pressure switch detects if the pressure of a calibration gas is low, which can be caused by an empty gas bottle, a disconnected gas line, etc. Calibration is prohibited when calibration gas pressure is low.
Circuit Board
The circuit board converts the incoming line voltage from AC to DC for use by the solenoids, terminations, and the programmable logic device. The power circuit is protected by a 1.6 A, 250 V, fast acting fuse.
The board contains a programmable logic device (PLD) that has the electronics to energize and deenergize the solenoids based on a signal from the Oxymitter 4000.
A terminal strip provides convenient access for all signal and power user connections.
Calibration Gas Flow Meter
The calibration gas flow meter indicates the flow rate of calibration gas flowing to the Oxymitter 4000.
Reference Air Flow Meter
The reference air flow meter indicates the amount of reference air continuously flowing to the Oxymitter 4000.
Pressure Regulator
The pressure regulator ensures the instrument air (reference air) flowing to the Oxymitter 4000 is at a constant pressure [20 psi (138 kPa)]. The regulator also has a filter to remove particulates in the reference air and a drain valve to bleed the moisture that collects in the filter bowl.