UM-0085-B09
DT80 Range User Manual
Page 333
RG
DI2 – Logic Inputs
Actively driven logic signals can be directly connected to all input channels, provided that the input levels are within the
specified limits; see
.
Figure 156: Wiring for reading TTL level signals on digital inputs
To measure
Use the command
state
1DS
(0 = low, 1 = high)
Other Considerations
Scan Rate
The digital input channels are scanned at 17ms intervals (60Hz), while the DT80 is awake. This means that the minimum
input pulse width is
17ms
– shorter pulses may not be recognised.
Schedule Triggers
Digital input transitions can be used to trigger a report schedule, or a schedule can be configured to only run if a digital
input is in a particular state.
See
Trigger on External Event (P53)
for more details.
Sleep Mode
Digital inputs are not scanned while the DT80 is asleep.
However, a high to low digital input transition can be used to wake the DT80 by connecting the digital input in parallel
with the
WK
(wake) terminal. The DT80 can then be programmed so that each time an external pulse occurs the DT80
will wake and run an event triggered schedule.
For example, if digital input 4 is also wired to the
WK
terminal then a typical schedule definition might be:
RA4-E 1..3TT
Note:
the digital input must stay low until the DT80 is fully awake. A short pulse (less than about 1-2 seconds) will still wake the logger,
but the DT80 may not "see" the high-to-low transition, in which case the edge-triggered schedule will not run.
Digital Outputs
The DT80’s 8 digital I/O terminals (4 for DT81/82) can also be used as outputs, either individually, or as 4 or 8 bit words.
The following channel types are used to control the states of digital outputs:
Channel Type
Valid Channel Numbers Description
DSO
1
-
8
(DT80/85)
1
-
4
(DT81/82)
Digital State Output
: sets the state of digital output; 0=low, 1=high
DNO
1
-
5
(DT80/85)
1
(DT81/82)
Digital Nybble Output
: sets the state of four consecutive digital outputs starting at the
specified output.
DBO
1
Digital Byte Output
: sets the state of all eight digital outputs.
RELAY
1
Relay Output
: sets the state of the latching
RELAY
output: 0=open, 1=closed
WARN
1
LED output
: sets the state of the
Attn
LED: 0=off, 1=on
For example:
7DSO=1
sets output
7D
high
5DNO=5
(binary 0101) sets
8D
low,
7D
high,
6D
low and
5D
high
1DB=255
(binary 11111111) sets all outputs high
1RELAY=1
closes
RELAY
output contacts
Channel Options
The following channel options are applicable to digital output channel types:
•
channel factor
: for the multi-bit channel types (
DNO
,
DBO
), the channel factor is a bitmask which specifies
which digital outputs to alter. The default values for
DNO
and
DBO
are 15 and 255 respectively (i.e. set all bits)
Содержание DT80
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Страница 184: ...UM 0085 B09 DT80 Range User Manual Page 184 RG Figure 71 DT80 communications options ...
Страница 185: ...UM 0085 B09 DT80 Range User Manual Page 185 RG Figure 72 DT80 communications options integrated modem models ...