SD-50X
Loop Powered 4–20mA Panel Meter
The self-powered SD-50X uses a 4–20mA
loop to generate its own power source.
It can be used to measure a wide variety of process variables, including flow,
level, pressure and temperature.
› Simple front panel calibration
› Easy scaling using two input values
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› Displays up to 50,000 counts
Contents
1 - Speci cations ............................... 1
2 - Casing, Display & Connections ... 2
3 - Setup ............................................ 3
Appendix ........................................... 4
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Powered from 4–20mA current loop input signal. Min input 3.5mA, max continuous
input 100mA. 3.4V drop + 20Ω (equivalent to 3.9V at 20mA). Typically load is 200Ω.
Full scale ranges standard meter is adjustable to any display span between -19,999
SPECIFICATIONS
› Easy to read LCD display
› Low cost
› High accuracy
and +30,000. Max resolution (50,000 counts) from any signal input span between
3.5 and 27.5mA.
A/D converter 16 bit Sigma Delta
Accuracy ±0.02% of reading (plus 2 digits)
Temperature coe cient typically 30ppm/°C (plus 0.1 counts/°C for zero o set).
Conversion rate 3 readings per second
SD-50X -MAN-16V07 (1005)Copyright © 2016 De ne Instruments Ltd
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CASING, DISPLAY & CONNECTIONS
2.1 - Casing & display
Dimensions 47 x 95mm (1.85 x 3.74")
29mm (1.14") depth behind panel
Panel cutout 45 x 92mm (1.77 x 3.62")
Max panel thickness 7mm (0.28")
12.6mm LCD display 5 digits + descriptor digit (select dummy zero/°C/°F).
6 decimal point positions (see 3.2)
Display range -19,999 to 30,000
Over range display shows
_ _ _ _ _ _
Under range display shows _ _ _ _ _ _
2.2 - DIP switches
Le DIP switch Right DIP switch
Default setting
6’th digit = °F
6’th digit = °C
6’th digit =
dummy zero
Display lock = O
Display lock = On
Rejection lter = 50Hz
Rejection lter = 60Hz
2.3 - Typical application connections
This diagram (right) shows the typical connection for
an SD-50X display. The operational signal range of the
meter is 4–20mA. The acceptable input signal range is
Input HI Input LO
–
from 3.5-27.5mA. The signal must have a compliance
24V Loop
Supply
voltage of at least 4V (200Ω load).
SD-50X -MAN-16V07 (1005) Copyright © 2016 De ne Instruments Ltd
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Before you begin front panel setup, ensure that the DIP switch display lock is not on.
SETUP
3.1 - Two point calibration & scaling
Any display value between -19,999 and 30,000 may be entered during calibration
and scaling, but the maximum di erence between the low and high display values
cannot exceed 32,000 counts. Reverse scaling is accepted.
The input signal should be capable of adjustment between two output values for
which the required display value is precisely known. Scaling can be accomplished
with as little as 0.1mA di erence between high and low input signals, however full
scale accuracy usually requires at least a 4mA di erence.
A Press and at the same time to enter the setup menu.
B Use the and buttons to select CAL ON. Then press once to accept
and enter the low input mode.
C LO IN appears on the display. Use the and buttons to adjust the display
value to any reading between -19,999 and 30,000. Apply the 4mA low input
calibration signal to the meter. Then press to accept the low input calibra-
tion value and proceed to high input mode.
If the input signal is disconnected a er this step, the low input values are saved and the meter
automatically returns to the high input mode when signal power is reapplied.
D HI IN appears on the display. Use the and buttons to adjust the display
value to any reading between -19,999 and 30,000. Apply the 20mA high input
calibration signal to the meter. Then press to accept the high input calibra-
tion value and go back to the operational display.
3.2 - Decimal point setting
A Press and at the same time to enter the setup menu.
B Press once to skip past calibration mode and enter decimal point mode.
C Use the and buttons to adjust the decimal point to the desired position.
Then press to return to the operational display.
SD-50X -MAN-16V07 (1005)Copyright © 2016 De ne Instruments Ltd
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APPENDIX
A - Error handling
by disconnecting from the power supply
during programming. To clear this error,
Calibration error display [CALERR] If
the di erence between the high and
low input signal is less than 0.1mA, or
if the di erence between the [HI IN]
and [LO IN] exceeds 32,000 counts, the
meter displays [CALERR]. The previously
calibrated scale factor is restored.
Loss of input signal power during calibration If the input signal is disconnect-
ed, a er the LOW input signal has been
applied and the button pressed, the
[LO IN] value will be retained. When the
signal power is reapplied, the meter automatically returns to the calibration [HI
IN] mode. This feature is useful when
the calibration signal cannot be adjusted between two known values without
disconnecting.
Memory error display [EE Err] This indicates that the memory has been corrupted. Memory errors are usually caused by
a faulty 24V DC power supply (only use
an Instrument Quality power supply), or
press the , and buttons at
the same time for a few seconds. This
will reset the meter, clearing all errors
and necessitating recalibration.
B - Proportional scaling
There is a 32,000 count maximum di erence permitted between the [Lo in] and
[hi in] display values selected during calibration. To have a display span greater
than 32,000, it is necessary to proportionally scale and calibrate the meter at
less than the full input signal span.
E.g. Proportional scaling at 50% of full scale:
An input of 4–20mA is required to read -19,999
to +30,000. The signal span is 16mA and the
display span needed is 50,000 counts. A signal
change from 12mA to 20mA (8mA=50% of signal span) produces a display change from 5,000
to 30,000 (a 25,000 count change). With a [Lo
in] signal of 12mA set to 5,000, and a [hi in]
signal of 20mA set to 30,000, the display will
then read from -19,999 to +30,000.
Or, with a [Lo in] signal of 4mA and the display
set to -19,999, and with a [hi in] signal of 12mA
and the display set to +5,000, the meter will display between -19,999 and +30,000.
De ne Instruments
New Zealand (Head O ce)
+64 (9) 835 1550
sales@de neinstruments.co.nz
www.de neinstruments.co.nz
SD-50X Document Revision Code: SD-50X-MAN-16V07 Date Code: 160919
United States (Dallas, TX)
(214) 926 4950
sales@de neinstruments.com
www.de neinstruments.com
South Africa (Pretoria)
sales@de neinstruments.co.za
www.de neinstruments.co.za
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