Instruction manual

APPENDIX A. TROUBLESHOOTING
A-4
remote site answering and then a high pitch
tone, then the phone line is probably fine.
• If the modem dials but the remote site does
not answer, the SWF$ messages will be the
same as those given previously. First,
ensure that the correct number is being
called. Check the Net Description for the
remote site.
If the remote just rings and never answers,
check the following:
• Does the datalogger and DC112 have
power? Check 12 Volt supply for the
datalogger. The DC112 modem gets its
power (5 volts) from pin 1 on the 9-pin
SERIAL I/O connector.
• Check the 9-pin cable connecting the
DC112 to the datalogger. It should be
straight through, i.e., no lines crossed.
Check connections at both ends. Try a
spare 9-pin cable if available.
• Check the phone line at the remote site with
a standard telephone. Is the telephone line
properly connected to the DC112.
• The DC112 has a jumper to enable it to
answer the phone. Check that this jumper
is in the correct position.
If the phone is busy:
• Is someone else calling the site?
• If the line is always busy, disconnect the
DC112 modem and try the line. If the line is
still always busy there may be a problem
with the line and it should be checked by
the phone company. If the line is always
busy only when the DC112 is connected the
DC112 or datalogger may have a hardware
problem and should not be left connected
until the problem is determined.
• If the two modems seem to get a phone
connection but the base modem does not
detect carrier, or if carrier is detected but
communication is poor with many retires,
the phone line may be noisy or of poor
quality and should be checked by the phone
company. Experience has also shown that
some base modems do not perform as well
as others.
A2.3 MD9 COMMUNICATION.
The MD9 at the computer (MD9 base) should
be connected to the computer through an
SC532 interface. The switches in the base
MD9 should be set so the address is 255. The
computer dials the base MD9 to communicate
with remote dataloggers much like it would dial
a telephone modem. The first step is to verify
communication with the base MD9. Carefully
examine the network health screen. Note if the
base MD9 is red or blue along with the remote
that is not communicating or if just the remote.
This helps determine if the base is working or
not.
If multiple remote sites are in use with the base
MD9, do any of the remotes work? If some
sites work that would tend to indicate either a
Net Description problem or a hardware
problem for the remote sites that do not work.
To check communication with the base MD9,
examine the PORT ACTIVITY box on the
NetAdmin main screen. Select the COM port
used to communicate with the base MD9.
Select the RESET COUNTERS buttons.
Examine the CHARS TX, and CHARS RX, and
RETRIES boxes. The TX box indicates how
many characters are sent to the base MD9 and
the RX indicates how many characters are
received. The TX box will be non-zero when
communication is attempted. The RX will be
non-zero when the base MD9 responds. When
the base MD9 fails to respond, the TX box will
be growing larger while the RX box remains at
zero. If the RX box remains at zero, the
SWF$.LOG file will have warnings and faults
like the following. This indicates the base is not
communicating. Note that MD91 is the
datalogger station trying to be communicated
with.
'08-24-94 14:27:52','F','PC1','MD91','MD9
base failed to respond.'
'08-24-94 14:27:56','F','PC1','MD91','MD9
base failed to respond.'
'08-24-94 14:27:57','F','PC1','MD91','Link
failed.'
When communication with the base fails, any
communication with remotes will also fail. The
will probably be messages generated for the
various remotes. These messages may cease
when communication with the base works.