Table of Contents
Chapter 1: Functional Description
The humidifier isolation transformer isolates the humidifier heater from the mains voltage. The primaries
mains input comes from the relay board and is switched by safety relay 2. The dual primaries and secondaries
are connected in parallel for 115 volt operation and in series for 230 volt operation. The isolated secondaries
output voltage is equal to the mains input voltage..
The toroidal transformer is used to buck the mains voltage down to the range required for the elevating base
and canopy motors. The primaries mains input comes from the relay board and is switched by safety relay
2. The dual primaries are connected in parallel for 115 volt operation and in series for 230 volt operation. The
output voltage from each secondary is about 15 volts for both 115 and 230 volt operation and is input to the
relay board motor control circuits.
The two identical solid state relays (SSR's) are used to switch the isolated 115 volts to the radiant and incubator
heaters. The SSR's are mounted to the back wall of the electronics enclosure below the toroidal transformer.
The upper right SSR controls the incubator heater and the lower left controls the radiant heater.
The 8.4 NiMH battery is connected to the relay board. It is used to power the +5 STBY during power fail. The
battery charges only when the unit is powered on.
1.6.1 Rail and Heater Door Switches
There are seven switches used to determine the position of the canopy and the heater doors.
Two normally open switches on each heater door determine the position of the doors. Each switch is wired in
series with the corresponding switch on the other door. One pair of switches closes only when the doors are
fully open and the other pair closes only when the doors are fully closed.
There are 3 normally open switches in the right upright which are used to determine the position of the canopy.
The top switch closes when the canopy reaches the upper position. The middle switch detects when the
canopy is about half way down. The bottom switch closes when the lowest position is reached.
The unit will function as a warmer only if the two heater door open switches and the top rail switch are all
closed.
The system will control as an incubator only if the bottom rail switch and the two heater door closed switches
are all closed.
As the canopy lowers the system senses the closure of the middle rail switch, then looks at the heater door
closed switches. If they are not closed, the canopy will stop at that position and the Heater Doors Not Closed
alarm will activate. This insures that the canopy will not lower to the lowest position if the heater doors are not
closed.
1.7 DataLink Option
The DataLink option allows direct output of serial data to various remote monitoring systems, such as a
computer or commercial RS-232 monitor. The DataLink option board contains the electronic circuitry necessary
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Table of Contents
Troubleshooting
