Murata Electronics North America DNT500P ユーザーズマニュアル
DNT500
2008 by RF Monolithics,
Inc.
51
M-0500-0000 Rev D
7. Troubleshooting
DNT500 not responding:
Make sure DTR is asserted (logic low) to bring the radio out of sleep mode.
Cannot enter protocol mode:
Make sure the host data rate is correct. The DNT500 defaults to 115.2 kb/s. If using the
escape sequence command, make sure a pause of at least 20 ms precedes the escape se-
quence.
A remote never detects carrier (DCD):
Check that the base station is running, and that the remote InitialNwkID parameter is the
same as the base station, or is set to 0xFF. Also check that remote is receiving an ade-
quate signal from the base station.
Carrier is detected, but no data appears to be received:
Make sure that RTS is asserted to enable receive character flow. Make sure the RF
transmit power is not on a high settings if the nodes are close together.
The DNT500 is interfering with other nearby circuits:
It is possible for the RF energy from the DNT500 to be rectified by nearby circuits that
are not shielded for RF, manifesting as a lower frequency pulse noise signal. If possible,
place the antenna at least 1 foot away from the transceiver module, and 3 feet from other
system circuit boards. Place sensitive circuits in a grounded metal casing to keep out RFI.
Range is extremely limited:
This is usually a sign of a poor antenna connection or the wrong antenna. Check that the
antenna is firmly connected. If possible, remove any obstructions in the near field of the
antenna (nominal 3 ft radius).
Transmitting terminal flashes (drops) CTS occasionally:
This indicates that the transmitter is unable to reliably get its data across. This may be the
result of an interfering signal, but most often is caused by overloading of the network.
Adjusting the protocol parameters may increase the network efficiency.
Receiving terminal drops characters periodically:
Set the number of retries to a high number and send a few characters. Check that the
transmitted data can get through under these conditions. Sometimes this symptom is
caused by an application that is explicitly dependent on the timing of the received data
stream. The nature of the RF channel imposes a degree of unpredictability in the end-to-
end transmission delay.
Make sure DTR is asserted (logic low) to bring the radio out of sleep mode.
Cannot enter protocol mode:
Make sure the host data rate is correct. The DNT500 defaults to 115.2 kb/s. If using the
escape sequence command, make sure a pause of at least 20 ms precedes the escape se-
quence.
A remote never detects carrier (DCD):
Check that the base station is running, and that the remote InitialNwkID parameter is the
same as the base station, or is set to 0xFF. Also check that remote is receiving an ade-
quate signal from the base station.
Carrier is detected, but no data appears to be received:
Make sure that RTS is asserted to enable receive character flow. Make sure the RF
transmit power is not on a high settings if the nodes are close together.
The DNT500 is interfering with other nearby circuits:
It is possible for the RF energy from the DNT500 to be rectified by nearby circuits that
are not shielded for RF, manifesting as a lower frequency pulse noise signal. If possible,
place the antenna at least 1 foot away from the transceiver module, and 3 feet from other
system circuit boards. Place sensitive circuits in a grounded metal casing to keep out RFI.
Range is extremely limited:
This is usually a sign of a poor antenna connection or the wrong antenna. Check that the
antenna is firmly connected. If possible, remove any obstructions in the near field of the
antenna (nominal 3 ft radius).
Transmitting terminal flashes (drops) CTS occasionally:
This indicates that the transmitter is unable to reliably get its data across. This may be the
result of an interfering signal, but most often is caused by overloading of the network.
Adjusting the protocol parameters may increase the network efficiency.
Receiving terminal drops characters periodically:
Set the number of retries to a high number and send a few characters. Check that the
transmitted data can get through under these conditions. Sometimes this symptom is
caused by an application that is explicitly dependent on the timing of the received data
stream. The nature of the RF channel imposes a degree of unpredictability in the end-to-
end transmission delay.