Sterlco M2B+ Controller - Manual (Page 27)

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4-6 Setting Up Cascade Control
The controller is provided with an internal cascade control feature. Cascade control is used to
enable a process having multiple lags to be controlled with the fastest possible response to
process disturbances. The system uses a remote control probe in the downstream process and
a local delivery and return probe in the TCU. The controller uses the remote probe to drive
the heating and cooling outputs, while the local delivery probe is the process fluid
temperature limit control. To set up this feature you must have access to the Secure Menu.
See Section 2-6 on page 16 to review accessing the Secure Menu.
V1.09C-V2.01 Cascade Set-up
• Turn Power on. The controller will go through an initialization sequence.
• After the sequence is complete, turn the controller on with the start button. The
controller will be defaulted to SECURE 3; To access parameters in the secure
menu the controller must be in SECURE 4.
• Index to secure menu, press enter, Use the up arrow to scroll to “111”, press
enter. The controller secure menu is unlocked.
• Scroll down to the SENSOR MONITOR menu, default is OFF. Depress the up
arrow to display=CNTL depress enter. The controller is now set for cascade
control.
• Scroll to the menu MOLD SENSOR type. Press the up arrow to display = RTD.
This is the setting for a 100 ohm RTD for the remote probe. For 1K ohm, select
RTD1K.
• Continue to scroll through the menu until the control goes back to the run menu.
Or wait one minute without touching a key. The controller will return to the run
mode automatically.
• The remote probe input is wired to Header J5, pins 3 and 4 on the back of the
controller. The remote probe is factory defaulted for a Type J T/C input. Move
the jumper “JMP2” to pins 1 and 2 for a RTD input.
• The controller process display will reflect the customer’s remote temperature. DT
(local to process temperature) will appear to the right of the Delta T temperature.
• If the local PID parameters are known, enter them for the inner loop parameters.
If they are unknown, take the controller out of the cascade mode by setting the
SENSOR monitor selection to OFF. Press the TUNE button. The parameters will
be written into the primary menu.
• Return the controller to the cascade mode.
• Press the TUNE button again to tune the controller to the customer’s process.
When the tune is completed, the PID parameters will be written into the
PRIMARY menu.
• Both the inner and outer loops can be viewed or adjusted in the PRIMARY
menu.