Teledyne 6400A - Sulfur dioxide analyzer - Manual (Page 154)

TAI Model 6400A SO
2
Analyzer Operator Manual, 02164, Rev. G
9-36
9.3.2.2 RS-232 Diagnostic Procedures
There are several features of the 6400A to make connecting to RS-232 and diagnosing RS-232
faults easier.
There are two LED's on the rear panel Connector Board which are connected to pin 2 and 3 of
the DB-9 connector on the board. If the jumper block is in the DCE position (default) the red
LED is connected to pin 3 of the DB-9 connector. When data is transmitted by the 6400A the red
LED will flicker, indicating data present on this line. When the 6400A is running, the LED will
normally be ON, indicating logic low. A one second burst of data can be transmitted over the
port by a command in the DIAGNOSTIC menu. Press SETUP-DIAG, scroll to select RS232 and
press ENTR to transmit a burst of lower case "w"'s.
The green LED is connected to pin 2, if the jumper block is in the default DCE position, this is
the pin on which the 6400A receives data. It is ON if an outside device is connected. This LED
gets its power from the outside device. When data is being transmitted by the outside device to
the 6400A this LED will flicker.
When you are attempting to configure the RS-232 port, if either of the LED's go out when the
cable is connected, that generally means that there is a grounding problem. Check the relative
ground levels of pin 5 on the DB-9.
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 line independently addressable, and 4 independent analog output
channels. The analog input channels are connected to V/F converter capable of 80,000 counts,
which is approximately 16 bit resolution. The integration period is software selectable from 40m
sec to 2.4 sec. 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
00514.
The overall operation of this board is quite complex. To fully check it out in all of its operational
modes is not recommended 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 multiplexed 16 channel. 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 ± 100 mV
If the 6400A 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.