16
Installation, Operations & Maintenance Manual
SECTION 3 - OPERATION
3.3 CONTROL RANGE ADJUSTMENT
First remove the cover from the ECC. On the ECC
circuit board,
Figure 11
, are four lights and four
small trim potentiometers. The lights are in pairs.
The pots are for zero, span, upper limit, and lower
limit adjust.
THE LIMIT POTENTIOMETERS
MUST BE SET BEFORE
CHANGING THE CONTROL RANGE. THEY MUST BE ADJUSTED
(AS THEY ARE AT THE FACTORY) TO PREVENT OVERTRAVEL
OF THE CONTROL SPOOL. IMPROPER ADJUSTMENT OF
THESE UPPER AND LOWER LIMIT TRIM POTS MAY RESULT IN
DAMAGE TO THE PUMP OR THE ECC.
1. Energize the ECC with AC power.
2. Make sure that the appropriate jumper plugs
have already been either removed or installed
to establish the desired mode of action
(direct action or reverse action) as described
earlier in this section.
3. Locate the “Zero” (VR2) and “Span” (VR1)
adjust controls on the printed circuit board (PCB)
shown in
Figure 11
.
4. Apply the lower limit input signal to the unit. For
a 4-20 mA operating range, this signal will be
4 mA; (for a 12-20 mA range, the lower signal
will be 12 mA).
5. Turn the “Zero” (VR2) adjust control until the
pump capacity indicator ring moves to the
desired point or until no further adjustment is
possible, whichever comes first.
6. Apply the upper limit input signal to the unit
(this will be 20 mA).
7. Turn the “Span” (VR1) adjust control until
the pump capacity control knob moves to the
desired point.
8. Repeat Steps 4 through 7 until the desired
results are achieved.
