Setting up analog inputs for flow - Triatek - LIT-12014409 - HMS1655 Fume Hood Controller

HMS1655 Fume Hood Controller User Guide

Product name
HMS1655 Fume Hood Controller
Document type
User Guide
Document number
LIT-12014409
Revision date
2024-05-27
Product status
Discontinued

You can configure the HMS1655 to calculate and monitor the real-time air change rate with one of three types of air flow input methods or sensors.

To configure one of the secondary analog inputs for air flow measurement from the configuration screen:
  1. Tap Select Input Type > Flow > Next.
  2. The Flow Sensor Input configuration screen appears. You can select which type of sensor to use to measure air flow.
  3. After you select the type of sensor to measure air flow, tap Next to open two configuration screens where you can specify the minimum and maximum flows the sensor supports.
  4. Enter these values in the engineering units that correspond to the type of sensor. For example, the units are either in.W.C or Pa for differential pressure (DP) transmitters.
  5. After you specify the air flow range for the sensor, tap Next to open the Analog Input x Settings configuration screen, where you can specify whether or not to calculate and display air changes on the main screen, as well as the range of the input signal for voltage or current, for the air flow sensor.
  6. If air changes selected for display and the flow measurement device are either a DP transmitter or a velocity sensor, tap Next to open the configuration screen.

You can use the Enter Duct Area configuration to specify the cross-sectional area of the duct in in.2. You can use the cross-sectional duct area to convert the differential pressure or velocity to a flow, which then calculates the air change rate.

To find the cross-sectional area of round ducts, multiply the radius squared by pi (3.1416). For example, the cross-sectional area of a round 12 in. duct, which has a radius of 6 in., is calculated as:

Arearound duct = π x r2 = 3.1416 x (6 in.)2 = 113.09 in.2

For rectangular ducts, the cross-sectional area is determined by multiplying the length by the width. As an example, the cross-sectional area of a duct that is 24 in. by 12 in. is calculated as:

Arearectangular duct = L x W = 24 in. x 12 in. = 288 in.2

After you enter the cross-sectional area of the duct in in.2, if you select air changes for display, enter the room volume in cubic feet at the Enter Room Volume configuration screen. The room volume calculates the real-time air change rate based on the calculated or measured flow. To calculate the volume of a rectangular room in cubic feet, multiply the length by the width by the height of the room. To find the volume of irregular shaped rooms, break the room into smaller areas and sum the individual volumes.

If you select the air changes for display and the flow measurement device is an actual air flow sensor, tap Next to open the configuration screen to enable you to specify the volume of the monitored room. The room volume is required to calculate the air change rate.