Emerson Tescom ER5000 Series, User Manual, Page: 233 / 248

ER5000 —
233
Internal Variables
ER5000 Pulse Width Modulation (PWM) Control Variables
12 ID_PWM_SHUTOFF_FLAG
This flag is only active if variable #13 (ID_RTTASK_DELAY) is
not a 0 or 1 and designates what the ER5000 will send to the
PWM every 25ms while it is delaying.
• 0 => Write the previously computed value to the PWM
• 1 => Write a 0 to the PWM
13 ID_RTTASK_DELAY
This variable is typically set to 0, allowing the control
algorithm to generate a new value for the PWM every 25ms.
Certain systems need a slower acting control system, which
is allowed for using this variable. For example, writing a 4 to
this variable will allow the control algorithm to compute a
new PWM value every 100ms.
19 ID_INNER_SENSOR_MIN
This variable operation is typically disabled by writing a 0 to
it. If not disabled, it allows for a minimum internal pressure. If
the internal pressure is below the specified value, the exhaust
valve will not be opened to decrease the pressure.
20 ID_INNER_SENSOR_MAX
This variable operation is typically disabled by writing a 4095
to it. If not disabled, it allows for a maximum internal pressure.
If the internal pressure is above the 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 ER5000’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 (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 (ID_MIN_EXHAUST),
sets the deadband for the system. This variable is solenoid