DATASONICS PSA-916, User Manual, Page: 15 / 26

PSA-916 Sonar Altimeter 3-4
Setup and Deployment Connection
where xx.xx can range from 0.80 to 99.99. If no echo was received the output
will be R99.99E<cr><lf>. If an echo was missed or the value does not meet
the averaging criteria then an “E” will be appended to the previous value. If
under range detection is selected and the value is under range then a ‘<’ will
be appended to the data.
If the unit is not functioning correctly, “E1,<cr><lf>” will be output. If this
occurs see section 4.4.3.
3.2.3 Error Output
This output is useful for indicating the validity of the data whenever the analog
output is the source of range output. This line will be a logic 1 (5 volts)
whenever no echo was detected in the last range interrogation cycle. If
averaging is enabled and the data does not meet the averaging criteria then
this line will be high. Essentially this line is high whenever it would be
necessary to output an E on the serial output. This line also goes high if error
condition E1 occurs. If this line is low it can be assumed that the altimeter is
functioning normally and the analog output is valid.
3.2.4 Analog Output
The analog output ranges from 0 VDC to 4.98 VDC, Which represents 0.00
to 99.99 meters. Note that if no echo is received, the output will go to full scale
(4.98 VDC).
3.2.5 External Key
This line is used to tell the PSA-916 to take a range reading. The altimeter
looks for a transition from a logic 1 (5 volts) to a logic 0 (0 volts). Once the
transition is detected the altimeter will take a range reading and wait 200ms
before looking for the next transition. Thus the minimum time between key
pulses is 200ms. However there is no maximum limit to the time between key
pulses. Note that the analog value will be valid 200ms after sending the
external key.