Instruction manual

APPENDIX A. TROUBLESHOOTING
A-3
cable. A straight through 9-pin cable
connects the SC32A to the datalogger.
• With RAD modems and the SC932, verify
the switch and jumper setting with those
given in the manual.
• Do a continuity test on the cable used
between the RAD modems.
• Do a loop back test to verify each RAD
modem.
• Does the hand-held keyboard display work?
If so, the datalogger has power and should
respond.
• Does the datalogger have power? Check
the 12 Volt supply with a volt meter.
A2.2 TELEPHONE
The first step is to determine if the computer
and modem are communicating correctly.
If multiple remote sites are in use, with the
phone modem, do any of the remotes work? If
some sites work that would indicate either a Net
Description problem or a hardware problem for
the remote sites that do not work.
To check communication with the modem. Check
the PORT ACTIVITY box on the NetAdmin main
screen. Select the COM port used to communicate
with the modem. Select the RESET COUNTERS
button. Wait until a call is attempted. Examine the
CHARS TX, and CHARS RX, and RETRIES boxes.
The TX box indicates how many characters are
sent to the modem 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 modem responds or
echoes characters. When the modem fails to
respond, the TX box will be growing larger while the
RX box remains at zero. This can also be verified
with external modems that have TX and RX lights.
If the RX box remains at zero, the SWF$.LOG file
will have warnings and faults like the following. Note
that STN2 is the datalogger station not the phone
modem at the computer. The first message will
occur whenever dialing is attempted and does not
indicate a problem.
'08-24-94 13:38:57','S','PC1','Stn2','Hayes
dialing: '' (COM1).'
'08-24-94
13:39:06','F','PC1','Stn2','Communication
with Hayes modem failed (COM1).'
'08-24-94 13:41:38','F','PC1','Stn2','Link
failed.'
When communication with the base fails any
communication with remotes will also fail. There
will probably be messages generated for the
various remotes. These messages should cease
when communication with the base works,
provided the rest of the communication is fine.
Check the following:
• Ensure the correct COM port is selected in
the Net Description for the modem.
• The modem is powered up?
• Check each cable to ensure it is connected
properly.
• The cable connecting the computer and the
modem should not be a “Null Modem” cable
but should be straight through.
• Are special dialing strings required?
• Once communication works with the base
modem, the phone line should be checked.
Again if the base modem works with other
sites, the phone line is probably fine.
• If the modem has a speaker, can the dial
tone be heard when dialing occurs? Does
the remote site ring and answer?
• If the remote modem does not respond then
the SWF$.LOG will have errors like these:
'08-24-94 13:42:15','S','PC1','Stn2','Hayes
dialing: '513' (COM1).'
'08-24-94 13:42:52','F','PC1','Stn2','Hayes
modem failed to detect carrier (COM1).'
'08-24-94 13:42:53','F','PC1','Stn2','Link failed.'
Notice the difference between these messages
and the previous ones, i.e., communication with
Hayes modem failed versus Hayes modem did
not detect carrier.
The following are things to check when no
carrier is detected:
• Ensure that phone line is plugged in the
proper jack on the modem. Most modems
have two jacks, one for the phone line and
one for a telephone. Use the jack labeled
“Teleco or To Line”. Attach the standard
telephone to the phone line being used and
manually dial the number. If you hear a
dial tone, the remote site ringing, the