Fluke Biomedical 859A-1-72 - Manual (Page 11)

Operation 4
4-1
Section 4
Operation
4.1 Operation
Once installation is complete and the field wiring is connected, operation is fully automatic.
Controller operation is centered at an 859-1-7136 Motor Control. The motor control receives – 12 VDC
unregulated power and then outputs pulses for the necessary stepping sequence at the sampler. The
unregulated – 12 VDC is supplied by an 859-1-7133 Power Supply. Output pulses are supplied to the
stepping motor in one of two ways. The internal timing circuit can be used to generate pulses, or an
external source can be used to generate the required pulses.
Internal pulses are generated through a 555 integrated timing circuit in the motor control. A rotary switch
is provided to connect the appropriate resistor-capacitor circuit to the 555 timer, which sends pulses to
the stepping motor. The operator has the option of choosing filter speed. The choices are: 0.5, 1, 2, or
10 inches per hour. The operator can also choose the FILTER CLEAR function. FILTER CLEAR is
accomplished using a pair of relays, which override the selected resistor-capacitor circuit. This generates
a fast input pulse to the motor controller and will advance a predetermined length of filter paper from the
859-1-50 Continuous Filter Air Sampler. The relays are initiated through a push button switch inside the
859-1-50 Continuous Filter Air Sampler. The filter advance time is determined by the adjustable timer
relay.
External pulses can be used to drive the stepping motor. Remember that proper operation of the moving
filter depends on the shape and timing of the input pulse. To use externally generated pulses, remove
the jumper wire connecting S and V on the motor control. This will disable the 555 timer.
Externally generated pulses are received by the controller at connector P1, pin K. Pulses must meet the
requirements shown in figure 4-1. To move the filter one inch per hour, the controller requires an input
pulse at 14-second intervals. All other filter speeds are shown in the Controller Adjustments section of
section 4.