Mercoid division – Dwyer CRF2 User Manual

Page 4

Printed in U.S.A. 11/12

FR# M1-443559-00 Rev. 6

MERCOID DIVISION

DWYER INSTRUMENTS, INC.

P.O. BOX 258 • MICHIGAN CITY, IN 46360 U.S.A.

Phone: 219/879-8000

www.dwyer-inst.com

Fax: 219/872-9057

e-mail: [email protected]

SETUP & CALIBRATION
Two multi-function buttons are provided for all calibration operations.
With these you can set the zero and span points, adjust the 4 and 20 mA
calibration points, or reset the 4 and 20 mA calibration points to the
factory settings. All settings are stored in nonvolatile memory so they will
not be lost if the power is removed.

Zero and Span Calibration
The zero and span calibration is done with the CRF2 installed in the
measured tank or vessel. Calibrating zero or span can be done in either
order as these settings are independent of one another. The calibration
can be done such that the output can go from 4 to 20 mA or from 20 to
4 mA depending on the desired measurement for full and empty
conditions.

The span or zero calibration is activated by pressing and holding the
corresponding ˝Zero˝ or ˝Span˝ button for three seconds. Set the tank
level to one endpoint (i.e., full or empty), then press and hold either the
Zero or Span button corresponding to the desired endpoint. Set the tank
to the other endpoint then press and hold the opposite Span or Zero
button. Calibration is now complete.

NOTE: Be careful to press the buttons only once within 3 seconds.
Double clicking the switches within 3 seconds will place the unit in
current calibration mode. If this happens press both buttons
simultaneously to exit the current calibration mode. If the calibration was
accidentally changed, the factory calibration can be restored as
described later in ˝Restore Factory Calibration˝.

Current Calibration
The 4 and 20 mA points of the CRF2 have been calibrated at the factory
and generally will not need to be recalibrated, but if needed the points
may be recalibrated. To do this you will need a milliammeter connected
in the current loop.

To calibrate the 4 mA calibration point, ˝double click˝ the Zero/4 mA
button by pressing it twice within 1.5 seconds. The milliammeter will
indicate approximately 4.00 mA. Adjust the 4 mA set point by pressing
the Zero/4 mA button to decrease the current and the Span/20 mA button
to increase the current. When complete, press both the Zero/4 mA and
Span/20 mA buttons simultaneously to exit the calibration mode.

To calibrate the 20 mA calibration point, ˝double click˝ the Span/20 mA
button by pressing it twice within 1.5 seconds. The milliammeter will
indicate approximately 20.00 mA. Adjust the 20 mA set point by pressing
the Zero/4 mA button to decrease the current and the Span/20 mA button
to increase the current. When complete, press both the Zero/4 mA and
Span/20 mA buttons simultaneously to exit the calibration mode.

NOTE: If the buttons are not pressed for approximately 4 minutes in
calibrate mode, the CRF2 will automatically revert to the normal
operation mode.

Restore Factory Calibration
The factory 4 and 20 mA calibration points may be restored by pressing
and holding both the Zero/4 mA and Span/20 mA buttons simultaneously
for 3 seconds. This must be done in the normal operation mode.

MAINTENANCE & REPAIR
Other than the controls mentioned in this manual there are no user
maintenance adjustments or routine servicing required for this product.
The unit is not field repairable and should be returned to the factory if
service is required. Disassembly or modifications made by the user will
void the warrantee and could impair the continued safety of the product.
If repair is required obtain a Returned Goods Authorization (RGA)
number and send the unit, freight prepaid, to the address below. Please
include a detailed description of the problem and conditions under which
the problem was encountered.

When the CLS2 with Sanitary Process Connection is to be used in a
sanitary or hygenic application, the unit must be cleaned and/or
sanitized in accordance with appropriate guidelines prior to installation.
The CLS2 with Sanitary Process Connection is suitable for “Clean In
Place” methods.

Dwyer Instruments Inc.
Attn: Repair Department
102 Highway 212
Michigan City, IN 46360

POWER

SUPPLY

RECEIVER/

READOUT

–

ZERO/

4-MA

SPAN/

20-MA

Figure 3: Electrical Wiring Diagram