On off, As shown in, The ttl signals are: 0vdc – Vaisala PTB220 User Manual
Page 40: And 5vdc, Pulse mode on
U
SER
'
S
G
UIDE
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34 ___________________________________________________________________ M210194
EN
-A
An external power control can be used to switch the PTB220
barometer
ON
/
OFF
. The control is activated with the switch SW2 in
position
ON
as shown in
F
IGURE
4-4
. The TTL signals are: 0VDC
OFF
and 5VDC
ON
.
ON
OFF
SW1
SW2
SW3
SW4
SW5
SW6
SW7
SW8
S1
F
IGURE
4-4
External power control ON
The pulse output mode is activated and the barometer starts to wait for
an external trigger pulse by turning the switch SW3 in position ON as
in
F
IGURE
4-5
. See Appendix D
for quick reference information on how
to set and use the pulse output mode of the PTB220 series digital
barometers.
ON
OFF
SW1
SW2
SW3
SW4
SW5
SW6
SW7
SW8
S1
F
IGURE
4-5
Pulse mode ON
NOTE
Switches SW6 and SW7 are usually in position OFF. However, for
some specific uses they may be turned ON to emulate other
barometers (see page 103 for further details).