FCU Equipment Control

Description

Define the main control features of controller outputs.

Purpose

Define the main control features of controller outputs.

Mode

Configuration can be performed with the wizard Off-line or On-line.

Procedure

  1. Click the Equipment Control button on the left pane to open the Equipment Control Configuration page.
  2. Enter information into available fields.
  3. Click Commit to save the settings or Reset to revert to the last saved settings.
  4. Click Next to display the Fan Configuration page or Back to display the Inputs Configuration page.

Fields 

Name Definition
Output Options    Defines the operating characteristics of the two valve actuator outputs.
  • Output 1
  • Output 2

Define operation of output 1 and output 2 as configured in the Output page. The fields have the same meanings for both outputs.

  • Fan Interlock

Normally used to protect electric heating coils controlled by Output 1 or Output 2. Without this protection, heating coils can overheat. This option can also prevent ice-up or condensation build-up on cooling or compressor coils.

Yes

The fan always turns on for the run-up time before turning on the control output, to ensure air is flowing over the electric heating coil before turning on the electric coil. The fan continues to run after the electric coil is turned off, for the post-run time, to ensure the electric coil is cooled down before the fan turns off.

Similarly, for cooling coil condensation protection, the fan re-run and post-run times are observed.

Additionally, if the digital input is configured for fan fail detection, and the fan does not operate within the defined run-up time, then the control output is not turned on. This action also occurs if the fan fails during normal operation.

No

There is no interlock between fan operation and the control outputs.

  • Valve Direction

Define the operating direction of the valves for actuator types Floating, PWM, and Thermal.

Direct

To open, the valve is modulated from 0% to 100%.

Reverse

To open, the valve is modulated from 100% to 0%.

  • Min Stage Off Time

Define the minimum off-time for control outputs configured for operation as staged outputs. This setting is particularly useful for heat exchanger operation or compressor units. Each stage of the controlled output stays off for the minimum period of time before the controller turns it on again. The selectable range is 0 to 600 seconds.

Valve Runtime

This configuration parameter has three different functions depending on the control output type selected in Control Outputs.

(CONTROL OUTPUT TYPE = FLOATING)

The value is the actuator run-time in the range 20 to 600 seconds.

(CONTROL OUTPUT TYPE = PWM)

The value is the cycle period of the PWM output in the range 20 to 600 seconds.

(CONTROL OUTPUT TYPE = ONE, TWO OR THREE STAGE)

The value is the minimum on-time for each of the stages, for controlling compressor units.

Reheat Options Defines the control output level at which the electric reheat relay (relay 4) switches.
  • Switch Level

Define the control output level at which the electric reheat output switches on. Range 0% to 100%.

Use a setting of 5% where electric heating has priority over a water heating valve, for example, as the first heating sequence. Or use for electric heating control only.

Use higher settings, for example, 90%, where water heating has priority over electric heating. Or when electric heating is required during summer/winter changeover periods.

  • Hysteresis

Define the control output level (Switch level - Hysteresis) at which the Reheat control output switches off.

PWM Options Allows the full range of the PWM outputs to be configured. Many PWM-controlled devices cannot provide an output of 0% or 100% because a PWM output shows no switching at these percentages. Therefore, most PWM devices have a minimum duty cycle and a maximum duty cycle between which they operate from zero to full scale. The fields here allow you to configure the full range of settings. It is possible to swap the Zero and Full range values to achieve reverse operation for a PWM output.
  • Zero

PWM % duty cycle for fully closed position.

  • Full

PWM % duty cycle for fully open position.

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