QB1T & QB2T proportion INSTALLATION & MAINTENANCE INSTRUCTIONS

DESCRIPTION / IDENTIFICATION

The QB series valve uses Proportion- Air closed loop technology for Pressure control. It gives an output pressure proportional to an electrical command signal input.

The QB1 is a complete closed loop servo system consisting of valves, manifold, housing and electronic controls. Pressure is controlled by the use of two solenoid valves. One valve functions as inlet control, the other as exhaust. The pressure output is measured by a pressure transducer internal to the QB1 and provides a feedback signal to the electronic controls. This feedback signal is compared with the command signal input.  A difference between the two signals causes one of the solenoid valves to open, allowing flow in or out of the system. Accurate pressure is maintained by controlling these two valves.

The QB2 is similar to the QB1 but uses a double loop control scheme.  In addition to the internal pressure transducer, the QB2 receives an electrical signal from an external sensing device. This primary feedback signal is compared against the command signal input. This comparison is then summed with the internal pressure transducer signal. The gain of the circuit is such that priority is given to the external feedback signal. A difference between the command signal and the feedback signal causes one of the solenoid valves to be activated.

A monitor output is provided for the system measurement. All QB valves come standard with an analog voltage monitor output.

QB1 monitor output is an amplified signal from the internal pressure transducer.  QB2 monitor output is a buffered signal from the primary external transducer connected to the QB2.

For QB valves with model number TFEE or TFIE the monitor output is voltage. The monitor output is analog current, if the valve model number is TFEC or TFIC.  See ordering information for further details.

INSTALLATION

1. Apply a small amount of anaerobic sealant (provided) to the male   threads of the in-line filter supplied with valve.   CAUTION: USE ONLY THE THREAD SEALANT PROVIDED.   OTHER SEALANTS SUCH AS PTFE TAPE AND PIPE DOPE CAN MIGRATE INTO THE FLUID SYSTEM CAUSING FAILURES. 

 2. Install the in-line filter into the port labeled IN on QB valve. 

 3. Connect supply line to the in-line filter port.  Connect device being controlled to port labeled OUT on QB valve. 

 4. Mount valve accordingly. 

 5. The valve can be mounted in any position without affecting performance.  Mounting bracket QBT-01 (ordered separately) can be used to attach valve to a panel or wall surface. 

 6. Proceed with electrical connections.

RE-CALIBRATION PROCEDURE

All QB control valves come calibrated from the factory by trained personnel using precision calibration equipment.  The QB valve is a closed loop control valve using a precision electronic pressure sensor.   Typical drift is less than 1% over the life of the product.  If your QB valve appears to be out of calibration by more than 1%, it is not likely to be QB.   Check the system for plumbing leakage, wiring and electronic signal levels.   Verify the accuracy of your measuring equipment before re calibrating.   Consult factory if you have any questions or require assistance.  If the QB valve needs re-calibration, use the procedure described below:

QB1 VALVES

1. Identify the inputs and outputs of the valve using the model number of the valve, calibration card included with the valve, and the information provided in this sheet.

2. 2. Connect a precision measuring gage or pressure transducer to the OUT port of the QB. NOTE:  THERE MUST BE A CLOSED VOLUME OF AT LEAST 1 CU. IN. (17 CC) BETWEEN THE VALVE OUTLET AND THE MEASURING DEVICE FOR THE VALVE TO BE STABLE.

3.  Connect the correct supply source to the IN port of the QB, making sure the pressure does not exceed the rating for the valve (See Table 1).

4.  Locate the plastic calibration access cap on top of the QB valve and completely remove it.  Located underneath are two adjustment trim pots, Zero “Z” and Span “S”.  See figure 1 for pots location.

5.  NOTE:  Only use this step if your device is totally out of calibration.  If it is slightly out of calibration, omit this step and move on to paragraph

6.   Using a small screwdriver, turn both trim pots 15 turns clockwise.   Then turn both trim pots 7 turns counterclockwise.  This will put the QB roughly at mid-scale. 6. Make correct electrical connections as noted.  Make sure there is a proper meter in place to measure the command input to the QB.

7.  Set the electrical command input to MAXIMUM value.

8.  Adjust the SPAN pot until MAXIMUM desired pressure is reached (clockwise increases pressure).

9.  Set the electrical command input to MINIMUM value.

10.  Adjust the ZERO pot until MINIMUM desired pressure is reached (clockwise increases pressure).

11. Repeat ZERO and SPAN adjustments, which interact slightly, until QB1 valve is calibrated back to proper range.  Step 6 - 9.

12. Replace calibration access cap.