95
SC-F70
SC-F70
PID Operation Operating Instructions
7.4 Actuator Control Problems
Use this guide when the actuator (for control valve, etc) does not perform
as expected even though all panel operations are correct for manual
operation.
Note: This section describes an example with a general-purpose control
valve used as the actuator. If you are using a different actuator,
contact TLV.
Actions
Analysis
Measure the controller output to the actuator while
running test operation in MAN mode.
Output Voltage in LOC/MAN
∑
When the voltages measured
change proportionally:
Control valve may be the cause
of the problem.
See instruction manuals for the
control valve to continue
analysis.
∑
When measurement shows
about DC 0V, have the
controller serviced.
∑
When measurement shows
about DC 14V, the cable from
the controller to the control
valve is probably cut or
disconnected; check cable and
reconnect it.
Control Output
Output Voltage
0%
50%
100%
Control Output
10
4〜20mA
control valve
11
Measure the voltage over terminals No.10 and 11
with a current and voltage meter.
Note: Even if the output is in current mode, measure it
in DC voltage.
The output voltage changes proportionally with the
target value settings.
Note the polarity