9. ER3000 Internal Variables 49
specified value, the inlet valve will not be opened to increase the
pressure.
34 ID_OUTPUT - This is the value of the output from the controller. It is
this value which controls the ER3000’s valves. A positive number will
open the inlet valve and a negative number will open the outlet valve.
46 ID_SOLENOID - This variable determines which valve is open when
the output is positive or negative. In normal mode, (0 => Normal)
positive outputs open the inlet solenoid and negative outputs open the
exhaust solenoid. In reversed mode, (1 => Reversed) positive outputs
open the exhaust solenoid and negative outputs open the inlet solenoid.
This is useful in reverse acting systems (i.e. - in systems where
increasing the pressure causes the process variable to decrease).
47 ID_MIN_INLET - This is the minimum value for the inlet pulse width
modulator. The pulse width modulator’s value ranges from 0 to 250.
This variable (along with variable #48) sets the deadband for the
system. This variable is solenoid dependant and typically a value close
to 10. Larger values can give tighter regulation, but at a cost of more
gas being exhausted.
48 ID_MIN_EXHAUST - This is the minimum value for the exhaust pulse
width modulator. The pulse width modulator’s value ranges from 0 to
250. This variable (along with variable #47) sets the deadband for the
system. This variable is solenoid dependant and typically a value close
to 10. Larger values can give tighter regulation, but at a cost of more
gas being exhausted.
65 ID_PWM_VALUE - This is the value which is controlling the Pulse-
Width Modulators for the solenoids. Positive values represent the inlet
solenoid opening and negative values are for the exhaust solenoid. A
value of +/- 250 represents a 100% duty cycle (full on).
9.12 Gain/Offset Variables
39 ID_GAIN - This is the gain value. This value in c
onjunction with the
offset (variable #40) is used to form the feedback signal (see variable
#44):
feedback = gain * compensated_reading + offset.
0x0200 => 1/8 ( .2% adjustability)
0x1000 => 1 (.025% adjustability)
0x8000 => 8 (.003% adjustability)
40 ID_OSET - This is the offset value. This value in conjunction with the
gain (variable #39) is used to form the feedback signal (see variable
#44):
feedback = gain * compensated_reading + offset.
0x0000 => -1/2 FS
0x0fff => +1/2 FS
To Next Page
Loading...
