No Serial Communication - Intermec EasyCoder 501 XP Service Manual

17.9 No Serial
Communication
Intermec EasyCoder 501 XP – Service Manual Ed. 4
Description:
The following actions are valid for the standard serial interface
"uart1:" fi tted on the CPU board and to some extent also to
any other serial interfaces on optional interface boards. Also
see Chapter 17.8.
Possible Causes and Suggested Remedies:
• Communication setup mismatch.
- In the Test Mode, check that the printer and host are set
for the same communication parameters, such as baud rate,
parity, character length, stopbits, new line, and handshak-
ing. Some kind of handshaking, for example XON/XOFF or
RTS/CTS, is strongly recommended.
• Damaged RS 232 driver circuit.
- With the aid of an oscilloscope, or some kind of line analyzer
("break-out box"), verify that the interface signals to and
from the CPU board are correct. The RS-232 driver (IC304)
could have been damaged as a result of voltage transients
from the interface. Being socket-mounted, this circuit is easy
to replace. Repeated damage is, however, an indication of
insuffi cient cable screening, or the electrical environment
being too noisy.
• No supply voltage.
- Verify that the supply voltages +5V are present (see Chapter
15.5.
• No external +5V.
- Some external devices require current supply from the printer
(+5V.) Typically, this applies to the Intermec External Key-
board or a bar code scanner. The printer supplies max. 200
mA and is automatically turned off at higher loads. Check the
consumption of the connected device.
- The polyswitch (RP30 on the CPU board; RP1 on the Indus-
trial Interface Board; RP1 and RP2 on Double Serial Inter-
face Board) may be out of range and need to be replaced.
• Too long cables.
- RS-232
- RS-422 & RS-485 Max. length 1,200 metres (4,000 ft)
- Current Loop
• Input buffer on host overfl ow.
- The input buffer should normally be handled by the software
of the host. Increase the receive buffer in the printer to a large
value, restart the host to empty its input buffer and try again.
• No response from printer when running a custom-made program.
- The verbosity can be controlled by means of the Fingerprint
instructions VERBON/VERBOFF and SYSVAR(18.) In the
Intermec Direct Protocol, verbosity is disabled by default.
Check the program for instructions that may affect the ver-
bosity.
- Verify that the correct communication port is selected as stan-
dard IN/OUT channel.
Chapter 17
Max. length 10-15 metres (33-49 ft)
Max. length 500 metres (1,500 ft)
Troubleshooting
151