Terminology And Function Descriptions - Omron CQM1H series Operation Manual

Terminology and Function Descriptions

2-4

Terminology and Function Descriptions

Manual Manipulated Variable
Heater Burnout Alarm
Input Shift Value
242
The manual manipulated variable can be used only as a time-proportional ratio.
Control is continued based on the final output level when automatic control (ON/
OFF or advanced PID) is switched to manual operation. This function enables
the output to be controlled artificially without using RUN or STOP commands or
altering the input status (e.g., for sensor errors). An example of application is
shown below.
Output
0%
Auto
• The heater burnout alarm output is a latched output. To reset the heater burn-
out alarm output, either set the heater burnout alarm set value to 0.0 or turn the
power supply to the Unit OFF and then back ON.
• The heater burnout alarm settings are shown in the following table.
Setting
0.0
0.1 to 49.9
50.0
• Heater Current
If the heater current reaches 55.0 A or higher, a CT input error will occur and
E500 will be output if the heater current is being monitored.
• The current at which a heater burnout will be detected is calculated as follows:
Set value = (Normal current + current after burnout)/2
• The following condition must be met:
Normal current – current after burnout ≥ 2.5 A
Measurements will not be stable if the difference is less than 2.5 A. If the
difference is less than 2.5 A, wrap the wire around the CT two or three times
to increase the measured current. The heater current monitor function can
be used to measure the currents. Actual values can vary from calculated
values.
• An input shift value can be set to offset the indicated value from the actual mea-
sured value. For example, if the input shift value is set to 3.0 °C and the actual
measured temperature is 50 °C, the monitored temperature will be 53 °C.
• If the input shift value is set too large, a sensor error can occur near the upper
and lower limits of the temperature range even though the measure tempera-
ture is still within range.
Manual manipulated variable changed
Manual
Auto
Changed Changed
Operation
Heater burnouts will not be detected. The heater
burnout alarm output will turn OFF. This setting is used
to reset an alarm.
The detection level for heater burnout alarms.
Heater burnouts will not be detected. The heater
burnout alarm output will turn ON regardless of
RUN/STOP status. This setting can be used to check
wiring.
Section 2-4