Watlow Series 93 - Manual (Page 39)

W a t l o w S e r i e s 9 3 A p p e n d i x ■ A . 7
Appendix
Equipment Required:
• 300
Ω
, 1/2 watt 10% resistor.
• 4 - 1/2 digit Digital Multimeter.
Setup And Calibration
1. Connect the ac line voltage L1 and L2 to the proper terminals of the Series 93. See
Chapter Two. Set the multimeter to measure current.
2. Connect the multimeter in series with the 300
Ω
resistor to Terminal 9 Positive and 10
Negative on the Series 93 terminal strip. Use regular 20 - 24 gauge wire.
3. Apply power to the controller and allow it to warm up for 15 minutes. After warm-up
put the controller in the [`CAL] menu. See Figure A.3. Select YES. Press the
‰Advance key until the 4A0 prompt is displayed.
4. Press the ˆInfinity key twice to enter the manual mode. The controller is calibrating
when the % indicator light is on.
5. At the [`4A0] prompt, the multimeter should read approximately 4mA. Allow at least
10 seconds to stabilize.
6. Use the ¿Up-arrow/¯Down-arrow keys (reverse acting) to adjust the reading on the
multimeter for 3.85mA ± 0.10mA. Press the ‰Advance key.
7. At the [`2A0] prompt, the multimeter should read approximately 20mA. Allow at least
10 seconds to stabilize. The controller will leave the [`CAL] mode if one minute passes
between key activations, except for 4-20mA units.
8. Use the ¿Up/¯Down keys (reverse acting) to adjust the reading on the multimeter for
20.15mA ±0.10mA.
9. To conclude the 4-20mA output calibration, press the ˆInfinity key twice, then press
the ‰Advance key to reach the next prompt or to exit from the [`CAL] menu.
NOTE:
Before calibrating an
installed controller,
make sure all data
and parameters are
documented. See
the Setup and
Operation Tables in
Chapter Four.
NOTE:
When the % indica-
tor light is on, the
controller is auto-
matically calibrating.
Your sequence is
VERY important.
Always move to the
next parameter
before changing the
calibration equip-
ment.
4-20mA Output Field Calibration Procedure