What is the response time of a HI 3000 series controller?

If I am using a 4 channel HI 3030 weight controller for a check weighing application, how long does the item being weighed need to be on the scale in order to get a good weight reading ?

The time duration required on your scale to get an accurate reading is dependent on the controller's internal update rate, load cell recovery/settling time, and configuration settings.

The HI 3000 series units (which include the HI 3010, and the HI 3030) have 55 updates per second, or every 18.18 milli seconds (20 ms). So the instrument reports weight every 20 ms and the speed of weighing must include any averages at 20 ms each.

The WAVERSAVER setting will take an amount of time and must be included.

WAVERSAVER settings:
7.5hz = 60 ms
3.5hz = 120 ms
1.0hz = 500 ms
0.5hz = 1 seconds
0.25hz = 2 seconds

You must also include the amount of time it take for the product to get on and off the scale.

Do you need to tare the scale in between products to account for any scale buildup? (Any material left on the scale from the previous weighing session). TARE requires a full one second added to the update rate for proper motion tolerance calculations. Typically the scale is not tared in between each weighment, but tared when there is a break in the weighing. Tare values also help in determining a box weight is consistent. This saves the time required to tare the box weight. If you have to TARE in between each load you need to include time to place the box on the scale, load cell settling time, weight calculation time, MOTION calculation and then actual pressing of the button or sending the TARE command.  This requires a minimum of 1.1 seconds/.

Mechanical settling of the scale is usually minimal, but some scales may have side forces introduced as the product enters or exits the scale. Only testing would prove or disprove if any error amount is present. Mechanical settling of a load cell is considered extremely fast at 60 ms. Load cells and scales settle between 40 ms and 5 seconds. Your settling speed will vary with piping, higher capacities are slower, and the complexity of your weighing process.

Your weighing time may vary with weighing conditions, system design, and maintenance practices. A practical minimum weighing cycle time is approximately 500 ms. Less than this number would require constant monitoring for weight accuracy due to mechanical changes.  We would not expect anything less than 350 ms with the best installation and faster than normal load cells. 

These timing figures are considerably less using the HI6000 series or the new HI4050 with the new analog weigh scale card.

As of this posting time the potential limits are still being researched and established.  Weighing speeds of 60-80 ms is a good possibility.

These weight reading time make it seem like you have weight changes presented in blocks with large delays in between.  By using a rolling accumulation the last in is pushed out with the latest reading and provides a current filtered weight reading.

As newer products come available we are decreasing these wait and weight determination times. 

If you are interested in faster weighing times, contact your local hardy sale representative.  You can also call the factory application engineers.  Ask About our HI4050 CW Check Weigher, and filler dispenser module lines.