Monitoring and Operating the Controller
3/07 UDC3500 Universal Digital Controller Product Manual 227
Description
The “AM STA” selection of digital input creates a repeater station when the digital input
is closed. This is accomplished by a multi-selection from the digital input menu.
• “ACTION” is forced as “DIRECT”.
• “CONT ALG” is forced as “PD+MR”.
• Active setpoint is forced to 2SP.
• The Loop 1 PV is switched to “PV 2IN” for Loop 1.
• The Loop 2 PV is switched to “PV 3IN” for Loop 2.
• The tuning parameters used are the second set of parameters.
When the switch is open the unit becomes a normal controller with “CONT ALG” of
“PID A”, using tuning parameters set 1, SP, PV as IN1 and “DIRECT” or “REVERSE”
as selected by customer configuration.
Input 1 is typically the PV of some upper controller and Input 2 is typically that
controller’s output. If the upper control fails, the upper device or some watchdog opens
the digital input switch and UDC3500 back-up PID A control is active.
When the upper control reactivates, the digital input switch is closed and the
Auto/Manual Station becomes a repeater station and allows the upper control output
signal to pass through.
Configuration
There are some things to consider when configuring the controller.
The PV range stays as the IN1 range, even while IN2 is the PV when the switch is
closed; therefore:
• The IN2 HI must be less than or equal to the IN1 HI.
(Suggest: IN2 HI = 100.0)
• The IN2 LO must be greater than or equal to the IN1 LO.
(Suggest: IN2 LO = 0.0)
• The TUNING GAIN2 must be equal to (IN1 HI – IN1 LO) / (IN2 HI – IN2 LO).
See Table 4-22 for Configuration Procedure.
Table 4-22 Auto/Manual Station Mode Configuration Procedure
Step Operation Press Result
1
Select Algorithm
Set-up Group
Setup
Until you see:
Upper Display = SET
Lower Display = ALGORTHM
2
Select Control
Algorithm
Func
Loop 1/2
Until you see:
Upper Display = (available selections)
Lower Display = CONT ALG
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