Manual

34 Watlow Series 935A User’s Manual
Calibrating the 935A
Calibration requires a precision millivolt source with
thermocouple compensation, an adjustable 0-10 volt source,
and a decade resistance box.
• [tr50] and [tr00] calibrate the thermocouple span.
• [``tc] calibrates the ambient compensation.
• [r380] and [r`15] calibrate the RTD span.
• 0V is required when calibrating [tc00] and [r`15]
for remote set point calibration.
• 5V is required when calibrating [tc50] and [r380]
for remote set point calibration.
• When calibrating, calibrate all points for consistency in results.
• Allow the unit to warm up for 15 minutes before calibrating.
Quick Calibration
Restore:
Press all three keys
simultaneously until
[tc50] appears in the
display, press .
once and [`rSt] will
appear in the display.
Press and hold ß,
the display will show
[``no], press . to
change display to
[`YES]. Press and
hold . and ,
for 3 seconds to exit
the [`CAL] menu.
NOTE: Restore
Factory Calibration
[`rSt] = [`YES]
restores factory
calibration
values to all
calibration prompts.
Figure 8a -
Thermocouple Calibration
Figure 8b -
RTD Calibration
Calibration Menu
[tc50]
✓
tc50
[tc00]
✓
tc00
[``tc]
✓
tc
[r`15]
✓
r15
[r380]
✓
r380
[`rSt]
✓
rst
mV source = 50.000mV
Volt source = 5V
mV source = 0.000mV
Volt source = 0V
mV source = Temp. Compensation
Volt source = 0V
Decade Box = 15.00 ohms
Volt source = 0V
mV source = 380.00 ohms
Volt source = 5V
• Store TC counts at 50.000mV
• Store 5V remote set point
counts for use with TC
• Store ambient counts
at 32° F. Type J.
• Store low end RTD counts
• Store 0V remote set point
counts for use with RTD
• Store high end RTD counts
• Store 5V remote set point
counts for use with RTD
• Restore factory calibration
mV
source
Volt
source
S2
–
1
S1
+
2
–
3
+
45678
OT1IN OT2
POWER
Decade
Box
Volt
source
S2
–
1
S1
+
2
–
3
+
45678
OT1IN OT2
POWER
• Store TC counts at 0.000mV
• Store 0V remote set point
counts for use with TC