Temporary rs-485 connection option – Vaisala HMP155 User Manual
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USER'S GUIDE____________________________________________________________________
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Temporary RS-485 Connection Option
It is possible to have a temporary RS-485 connection also in the passive
output version by powering up the probe, while simultaneously holding
down the ADJ button, see Figure 13 on page 58. After the probe has
restarted, pins 2 and 6 then have the RS-485 signal. For the order of the
pins, see Figure 7 on page 20. The default signals are returned to the pins
after the next power-up.
The active output version with two voltage channels includes also a solid
RS-485 connection with dedicated signal pins that can be used as a
temporary digital service port. However, Vaisala does not recommend
the continuous, parallel use of both digital and analog outputs, because
this may affect the temperature measurement accuracy due to increased
power consumption and probe self-heating.