EPSW-TS-RTD-6P-R1
Larson Electronics, LLC
Phone: (800) 369-6671
Fax: (903) 498-3364
www.larsonelectronics.com
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Temperature Range Selection
The RTD Transmitter has 7 built in temperature ranges and a user settable range that are selectable by setting the
Dip Switch located inside the housing (Figure C). Switches 2, 3, and 4 are used to set the range. To set the desired
range, unscrew and remove the cover and set the Dip Switch according to the following table:
Selectable Ranges
Dip Switch
2
3
4
40 to 90°F (4.4 to 32.2°C)
-20 to 140°F (-28.9 to 60°C)
0 to 100°F (-17.8 to 37.8°C)
30 to 240°F (-1.1 to 115.6°C)
32 to 212°F (0 to 100°C)
32 to 122°F (0 to 50°C)
-30 to 65°C (-1.1 to 18.3°C)
User ettable
OFF
ON
OFF
ON
OFF
ON
OFF
ON
OFF
OFF
ON
ON
OFF
OFF
ON
ON
OFF
OFF
OFF
OFF
ON
ON
ON
ON
Setting and Calibrating the User Settable Range
By setting SWITCH 2, 3, and 4 on, the RTD Transmitter may be adjusted to a custom user specified range. The range
may be any values between –30°F and +250°F (-34 to +121°C) with a MINIMUM SPAN of 40°F (22°C).
Equipment Required
In order to calibrate the unit for a custom range, a precision RTD simulator that can simulate a 1000 OHM DIN type RTD
or precision decade box is required. The device must be capable of generating the correct RTD resistance to 0.1% or
better.
Calibration Procedure
1.
Set DIP SWITCHES 2, 3 and 4 ON.
2.
Remove the RTD sensor leads from terminals 5 and 6 (Figure B). Connect the
precision RTD simulator or
decade box to terminals 5 and 6.
3.
Wire instrument as previously discussed. A current meter may be wired in series
with the unit to verify the correct
current output, but this is not necessary for calibration. Apply power to the unit.
4.
If a precision RTD simulator is used, make sure it is set to simulate a 1000 OHM DIN 0.00385 RTD. Then set it to the
desired minimum temperature. If a decade box is used refer to the table in Appendix A (°F) or Appendix B (°C) and set
it to the resistance that represents the desired minimum temperature.
5.
Press the ZERO button. If the unit has the optional LCD, the display will read ZERO OK momentarily. If a current meter
is wired, it will read 4.00 mA.
6.
Repeat step 4 using the value for the maximum desired temperature.
7.
Press the SPAN button. If the unit has the optional LCD, the display will read SPAN OK momentarily. If a current meter
is wired, it will read 20.00 mA.
8.
Turn off power to the unit. Disconnect the RTD simulator or decade box and reconnect the RTD sensor to terminals 5
and 6. Calibration is complete.
Note:
The calibration procedure does not effect the calibration of any of the built in ranges.
°F and °C Selection
If the unit has the optional LCD display, DIP SWITCH 1 sets the display
to read in °F or °C. SWITCH 1 “OFF” = °F
SWITCH 1 “ON” = °C.
Output Current Display
If the unit has the optional LCD display, the lower display will show the output current if DIP SWITCH 5 is “ON”. Setting
DIP SWITCH 5 “OFF” causes the lower display to be blank.
Open RTD Protection
Upon detecting an open RTD, the unit may be set to force the output to read 3.5 mA or 21mA based upon the setting of
DIP SWITCH 6.
SWITCH 6 “OFF”, output forced to 3.5 mA
SWITCH 6 “ON”, output forced to 21 mA
