Shutter Mechanism Setup, Revision 1.00 

When assembling a shutter for the first time, or for checkout, perform the folowing.

The motor running current at 12.0 volts should be checked during rotation in both directions. 
Position the shaft vertically and allow the mechanism to make complete rotations while observing 
the current. The typical current will be 200mA. The current should not exceed 275mA for any portion
of the rotation. If it does, the source of friction must be corrected. Connector pins 1 and 4 are 
for motor power.

Any clicking noises from the mechanism, or visible binding must be investigated and corrected. 
It is important to insure that the antibacklash gear is set correctly. The spring should be 
tensioned before the motor drive gear is meshed, and care should be taken that it does not 
come loose during assembly.

The "home" or "closed" position is defined as the shaft position that causes the paddles to 
face directly away from the mechanism centerline. It is important that the potentiometer be 
set to the correct value at the closed position so that shutters can be interchanged without 
the need for software calibration.

The Potentiometer should be adjusted to 2879 ohms, plus or minus 50 ohms, at the closed position. 
Measure the resistance between connector pins 2 and 3. 

When attaching a shutter to a Spectroradiometer, be sure that the closed position of the paddles 
is still at 2879 ohms after assembly.

Connector pins:

The large pin is #1, pin #2 is counterclockwise from it.

1. Motor negative terminal.

2. Potentiometer terminal A.

3. Potentiometer terminal B.

4. Motor positive terminal.


Dave Wright 2:53 PM 10/27/97