
Teledyne API Model 200AH NOX Analyzer Instruction Manual, 06492, Rev. G2
9-37
Check that the voltage level on Pin 8 of the Analyzer is between +5 V and +15 V. This pin
should be connected (through the cable) to Pin 4 of the modem.
Now set the baud rate of the Analyzer to the speed required by the modem and it should work. If
you are still experiencing problems, a cable adapter may be needed. Please contact the factory
for assistance.
9.3.3. Voltage/Frequency (V/F) Board The V/F Board consists of 16 analog input channels, each software addressable, 8 digital inputs,
and 24 digital outputs, each independently addressable, and 4 independent analog output
channels. The analog input channels are connected to a V/F converter capable of 80,000 counts,
which is approximately 16 bit resolution. The integration period is software selectable from
40 msec to 2.4 secs. Commands from the SBC40 computer and digitized values from the V/F
section of the board are sent via the STD bus interface. The schematic for the board is in the
Appendix.
The overall operation of this board is quite complex, to fully check it out in all of its operational
modes is not possible in the field. Therefore a few of simple tests are described here that test one
analog input channel, the 4 analog output channels, one digital input, and one digital output.
1. V/F board analog input test.
Each analog channel is routed through a programmable 16 channel multiplexer. Chances are
that if one channel works, they all work.
A. Turn on instrument.
B. Press TEST key on front panel keyboard until DCPS test is displayed.
C. The value displayed should read 2500 200 mV.
If the M200AH passes this test, it has successfully digitized a 2500 mV composite voltage
output from the Power Supply Module. The signal should also be quiet 25 mV.
2. Analog output channel test.
In the DIAGNOSTIC menu on the front panel, there is a test that outputs a step voltage to the
4 analog outputs. This test is useful for calibrating chart recorders and dataloggers attached
to the M200AH. The test can also be useful in diagnosing faults in the V/F board.