UM-0085-B09
DT80 Range User Manual
Page 42
RG
The same channel can be put in the list more than once, with the same or different channel options. The DT80 treats
each occurrence as a separate measurement.
A Special Channel Option — Channel Factor
The DT80’s channel factor channel option is simply a floating point number. This number is interpreted in different ways
depending on the channel type, as indicated by the following table.
Channel Type
Channel Factor’s function
V
,
HV
,
T
x
,
CV
,
SV
,
CALC
,
&
name
,
MODBUS
,
SDI12
,
internal channels e.g
.
VBAT
,
REFT
Scaling factor – for example,
1V(5.5)
means multiply the reading by
5.5
LM
x
35
(voltage output)
External voltage divider factor, or slope calibration factor
I
,
L
,
AD5
xx
,
TMP17
(current)
Resistance (ohms) of the external current shunt (the
DT80
uses this value and the
voltage it measures across the shunt to calculate current flow)
LM
xx
,
TMP3
x
(voltage output)
Offset adjustment (°C)
BGI
(current excited bridge)
Bridge arm resistance (ohms)
BGV
(voltage excited bridge)
Offset adjustment (ppm)
PT3
xx
,
NI
,
CU
(RTD)
Resistance of the RTD element at 0°C (ohms)
YS
xx
(thermistor)
Value of connected parallel resistance (ohms)
R
(resistance)
Offset adjustment (ohms)
AS
(state)
Logic threshold value (mV)
F
,
FW
(frequency)
Sample Period (ms)
C
,
HSC
,
ST
x
(counter, timer)
Count modulo value (reset after every n counts)
DN
,
DB
,
DNO
,
DBO
(digital multiple)
Bitmask (only channels with 1 in bitmask are read/output)
DSO
,
WARN
,
RELAY
,
PWR12V
,
PWR5V
(digital output)
Delay time (ms)
SERIAL
Timeout (sec)
For example, the three channel definitions in the schedule command
RA30S 1V(10.1) 4PT385(200.0) 2DSO(100,R)=0
contain channel factor channel options that instruct the DT80 to do the following:
•
scale (multiply) the voltage measured on input channel 1 by 10.1
•
use 200.0Ω (instead of the default 100.0Ω at 0°C) when calculating the temperature represented by the signal
from the RTD on channel 4
•
output a 100ms pulse on digital channel 2.
Multiple Reports
The DT80 samples each channel in the channel list once every scan. However, by adding additional channel option sets
(each set enclosed in round brackets) you can generate additional reports. That is, you can report the same data value in
different ways.
The first channel option set determines how the channel is sampled, and must include all sampling options required for
the channel. These channel options are listed above the configuration line in the Channel Option Table
. Second
and subsequent option sets may only contain reporting options (those below the configuration line.
Multiple reports are particularly useful for statistical reports (see
Statistical Report Schedules (P57)
) in that several
different statistical operations can be performed on the same data set.
For Example:
RA1H 3YS04(II,AV)(MX)(TMX)(MN)(TMN)
defines five option sets. The first option set specifies one sampling option (
II
– use 2.5mA excitation) and returns the
average temperature value, calculated over the period (1 hour in this case) since the last report scan. The remaining
option sets will return the maximum reading over the same interval, the time at which it occurred, the minimum and the
time of minimum.
Remember that the first option set can contain options from any part of the channel option table, while subsequent option
sets can only contain options from below the configuration line.
Mutually Exclusive Options
Options grouped by a shaded rectangle in the Mutual Exclusions column of the table below are mutually exclusive. If
more than one channel option from a mutual exclusion group is placed in a channel list, only the last one specified is
recognised.