Watlow Electric Micro-Based Autotuning Control SERIES 980/985 - Manual (Page 38)

Figure 34 -
The Calibration
Menu.
NOTE
Before calibration
on an installed
control, make sure
all data and
parameters are
documented. See
Setup and Operation
Charts, Pages 26
and 28.
NOTE:
Not all parameters
will appear. They
are dependent on
your unit type. Use
only the steps that
apply to your unit.
tcL
tcH
4A0
Thermocouple Field Calibration Procedure
Thermocouple, low end uncompensated. 0 mV
Thermocouple, high end uncompensated. 50mV
Thermocouple compensated value reference.
RTD low end resistance, see Table 2 on Page 39.
RTD high end resistance, see Table 2 on Page 39.
Process input. 0V
Process input. 5V
Process input. 4mA
Process input. 20mA
Process output. 4mA
Process output. 20mA
Restore factory calibration values. See Page 37.
Factory use only.
Factory use only.
Equipment Required
l
Type “J” Reference Compensator with reference junction at 320F/0°C, or
Type “J” Thermocouple Calibrator set at 320F/0°C.
l
Precision millivolt source, 0-50mV min. range, 0.01 mV resolution
Setup And Calibration
1. Connect the AC line voltage Ll to Terminal #4, L2 to Terminal #7, and
Ground to Terminal #8. Jumper for correct line voltage. See Chapter 2.
2. Connect the millivolt source to Terminal #18 Negative and Terminal #20
Positive on the 980/985 terminal strip. Use regular 20 - 24 gauge wire.
3. Apply power to the unit and allow it to warm up for 15 minutes. After
warm-up put the unit in the CAL menu. See Figure 33 on Page 37.
IMPORTANT:
When the MANUAL LED is ON the unit is automatically calibrating. Your
sequence is VERY important. Always move to the next prompt before
changing the calibration equipment.
4. Press the AUTO/MAN key twice to enter the MANUAL mode. The unit is
calibrating when the MANUAL LED is ON.
5. At the “tcL” prompt, enter 0.00 millivolts from the millivolt source to the
control. Allow at least 10 seconds to stabilize. Press the MODE key.
6. At the “tcH” prompt, enter 50.00 millivolts from the millivolt source to the
9801985. Allow at least 10 seconds to stabilize. Press the MODE key.
7. At the “tc” prompt, disconnect the millivolt source, and connect the
reference compensator or T/C calibrator to Terminal #18 Negative, and
Terminal #20 Positive on the Series 980/985 terminal strip. Allow 10
seconds for the control to stabilize. Press the AUTO/MAN key twice to
exit the MANUAL mode. This pauses calibration to allow you to exit the
CAL mode.
38
WATLOW Series 980l985 User’s Manual Appendix