User configuration settings - Titus - LIT-12014051 - Valve - Venturi Valve

Titus Venturi Air Valve Installation Guide

Product name
Venturi Valve
Document type
Installation Guide
Document number
Revision date

The CFM/Press at 10 V field sets the control signal and feedback signal scale in and out of the UVM. If the UVM is configured to operate with a Venturi valve, this value represents what CFM the 10 V input and output signals represent.

For example, if you enter a value of 1500 CFM, a 10 V signal applied to the IN connection requests 1500 CFM, and a 10 V signal from the Vo connection indicates that the valve provides 1500 CFM. This value is set initially by the factory and is matched to the size of the valve attached to the UVM. The typical values are:
  • 8 in. = 800 CFM
  • 10 in. = 1100 CFM
  • 12 in. = 1600 CFM
  • 14 in. = 2300 CFM

The FB input filter factor is a filtering or dampening factor applied to the raw feedback signal from the position feedback sensor on the valve. The typical value is 3.

The SP input filter factor is a filtering or dampening factor applied to the raw control signal applied to the IN connection of the UVM. Some third-party controllers use a PWM method to produce their AO signals. This method typically results in a signal that varies by up to 0.5 V at 10 KHz. The UVM is sensitive to this signal and results in an actuator that moves between various positions as it follows the moving input control signal. This value is typically 10 to 20 but can be 50 or more for third party controllers with unsteady AO signals.
Note: The higher this value, the less responsive the UVM is to sudden changes in the control signal.

The Gain PressSen and Offset PressSen fields can scale an optional external pressure sensor, so the sensors output voltage range converts to the appropriate pressure range on the UVM. The use of a pressure sensor as a DP monitor is active only when the Use Press Sens as DP selection is active. The pressure sensor can be used to monitor the DP pressure across the valve and give a 0 CFM output voltage if the pressure falls below the value set in the No Flow Press field, typically 0.6 in. W.C.

When an analog pressure sensor is used with a voltage output connected to the Sens_In pin, use the following scaling. Refer to the UVM1000 Universal Valve Module Installation Guide for more information:

The scaling is derived from : 0 V = 0 counts, 5 V = 4095 counts = x Press = (x – Offset) * Gain

Gain = ( ( Ph – Pl ) / ( Vh – Vl ) ) * ( 5 / 4095 )

Offset = ( 4095 / 5 ) * ( Vh – ( Ph * ( ( Vh – Vl ) / ( Ph – Pl ) ) )

Where Vh is the sensor voltage at the high-pressure Ph, and Vl is the low voltage at the low-pressure Pl.

To enable to automatic calculation, click the Calc button.

The Calc button opens a calculation dialog where the sensor pressure range and output voltages can be entered. The Compute button calculates the gain and offset and enters these values in the Gain PressSens and Offset PressSens boxes. If these values are correct, click the Set PressSens Gain and Set PressSens Offset button to send the values to the controller.

The in. W.C. pressure, which deems the flow in the valve to be invalid and produces a 0 CFM flow feedback signal, is entered in the No Flow Press field. For Triatek standard flow valves, this value is 0.6 in. W.G.

The Flow Sw Delay setting is used when a DP switch is connected to the valve that detects insufficient DP to produce a reliable CFM. The delay value is in seconds and is the time between when the DP switch detects a low flow and when the UVM zeros out the CFM feedback signal. This value is only relevant when the Use DI as DP or Use Press Sens as DP check box is checked.

The fit stroke time is for instances when a floating actuator is used with the UVM. The actuator counterclockwise (CCW) and clockwise (CW) inputs are connected to the CCW and CW outputs of the UVM. The actuator common and the UVM COM are connected to the active and neutral outputs of a 24 VAC supply. Ensure the Float DO is DP Out selection is unselected. The fit stroke time is the stroke time of the floating actuator, between 60 seconds and 90 seconds.
Note: Floating actuators are not very accurate for stroke time to determine position. The actual requested CFM and achieved CFM may not match.