Ultrasonic Flow Meter Connections & External Pins

External Ultrasonic Flow Meter Connections (Page 5)

Atrato ultrasonic flow meter connections can be configured as follows:

ultrasonic flow meter connections
Atrato ultrasonic flow meter connections

Ultrasonic Flow Meter Connections (Pins)

Pin 6 (NPN):

flow meter external connections pin 6

Pin 6 can be configured as either an output or an input but not both simultaneously. If one input and one output is required the user must determine whether they require a NPN or PNP output and use the appropriate terminal for each action. The options are:

  • Not used
  • Output
  • Input .

Pin 7 (PNP):

external connections pin 7

Pin 7 can be configured as either an output or an input but not both simultaneously. If one input and one output is required the user must determine whether they require a NPN or PNP output and use the appropriate terminal for each action. The options are:

  • Not used
  • Output
  • Input

Note: the operation for Pin 6 and Pin 7 are identical with the exception of the type of transistor output. These instructions are the same for Pin 7 except the Pin 6 (PNP) would read Pin 7 (NPN).


Pin 6 (PNP)/PIN 7 (NPN)

The contents of this box will change depending on the selection made in the External connection box.

If Output is selected the check box options are:-

  • Pulse
  • Single Flow Switch
  • Dual Flow Switch
  • Reverses Flow

ultrasonic flow meter external connections pin 6a

Pulse: Enter the number of pulses per unit volume required. This figure can be adjusted to suit the application and the flow range required from the meter. The maximum output frequency is 1000 Hz. So care must be taken to ensure that this pulse rate is not exceeded.

E.g. 10 L/min at 1000 Hertz equals (1000×60)/10 = 6000 P/L

Therefore 6000 pulses per litre is the maximum resolution for 10 litres per minute assuming maximum frequency output. If the meter is being used up to 5 L/Min the pulse output and so resolution could be doubled to 12000 P/L.

examples wiring for ultrasonic flow meters
Atrato Ultrasonic Flow Sensor: Example wiring for NPN and PNP pulse outputs

Single Flow Alarm

single flow alarm
Single Flow Alarm

Checking this option opens up input boxes for THRESHOLD; LATCHING and INVERT

Set the Threshold to the flow value you require the transistor to operate. The logic of operation can be adjusted with the INVERT check box (see left).

The Latching box gives the user three options of None; High Threshold and Low Threshold.

  • “None” will cause the alarm to be triggered when the threshold flow is met. The alarm state will then reset in accordance with the user set Hysteresis.
  • “High Threshold” will cause an alarm signal to Latch on when flow is seen above the set value
  • “Low Threshold” will cause an alarm signal to Latch on when flow is seen below the set value

Hysteresis (%): This is used when Latching is Set to NONE to prevent “fluttering” of the alarm signal when flow is around the threshold level.

LATCHED alarms will remain Active and the Local Display will show “LATCH” until they are reset. RESET LATCH ALARMS by either a signal Input on one of the other Input/Output PINS, or by Pressing and Holding the Right Hand Button on the Local Display on the Flow meter for 3 seconds.

Note the alarm points are driven by the display value on the “flow reading” screen. Any changes to the filter value of the display will affect the response time of the alarm points so there are two adjustable parameters to ensure “fluttering” does not happen with small flow fluctuations – response time and hysteresis.

INVERT – This Check box allows the user to invert the operation of the signal

Checked = Alarm output logic HIGH

For details see the Alarm logic table or hover mouse over the set point to see the action of the output with the chosen settings.


Dual Flow Alarm

dual flow alarm
Ultrasonic Flow meter dual flow alarm

Checking this will enable a range of flow to be entered. When the flow is outside/inside of this range the alarm will be triggered.
The remaining settings in the input box are the same as for Single Flow alarms.

  • When no Latching is chosen the alarm will automatically reset in proportion to the user set Hysteresis.
  • The Latched Alarm can be reset by a signal Input on one of the other Input/Output PINS, or by Pressing and Holding the Right Hand Button on the Local Display on the Flow meter for 3 seconds.
  • The INVERT checkbox will reverse the action of the alarm output. (see the Alarm Logic Table).

Reverse Flow

reverse flow alarm
Ultrasonic flow meter reverse flow alarm

This option allows the user to send a signal from the assigned wire/PIN when reverse flow is seen.
Selecting INVERT will reverse the action of the signal.

alarm logic table for ultrasonic flow meters
Ultrasonic flow measurement alarm logic table

If INPUT is selected either the Reset Total or Reset Alarm can be operated remotely by using a switch and resistor to apply a suitable voltage (between 5 and 24 Vdc) to either Pin 6 or Pin 7 as described on page 14.

Pin 6 : In input mode, the PNP open collector output is disabled, and the input pin responds to an external input voltage at TTL levels (VinH ≥ 2.4V; VinL ≤ 0.8V). This input must to be driven by an external voltage supply which can safely be in the full range of zero to the external supply voltage. Because of the potential for conflict should the PNP output be activated accidentally, Titan Enterprises Ltd recommend a resistor so that the sink current cannot exceed 5mA. An example circuit is given below:

pin 6, pin 8 and pin 9

Example Input to Pin 6

Pin 7 : In input mode, the NPN open collector output is disabled, and the input pin responds to an external input voltage at TTL levels (VinH ≥ 2.4V; VinL ≤ 0.8V). This input must to be driven by an external voltage supply which can safely be in the range of zero to 24V. Because of the potential for conflict should the NPN output be activated accidentally, Titan recommend a resistor so that the source current cannot exceed 5mA. An example circuit is given below:

external connections

 


Atrato Ultrasonic Flowmeter Relay

RELAY MODE: If the relay is required for a flow switch check the flow switch box and a further set of options for set point and hysteresis will appear.

 relay
Atrato Flow Meter Relay

Threshold: Set the required flow rate for the flow switch.

The Reset Offset (%) (Hysteresis) is either negative or positive depending on whether a falling or rising alarm is required.

The relay has change over contacts but to reduce power consumption the relay is off if positive hysteresis is selected and only powers when the threshold is exceeded.

If negative hysteresis is chosen the relay is on up to the set point.
The increments are preset and can be cycled through using the + &- buttons.

If more than one set point is required either both transistors must be used or one transistor and the relay.


Analogue outputs

Analogue MODE: There are four options on the drop down menu:
Not Used, 4-20mA, 0-5 Volt and 0-10 Volt.
Once the selection has been made a further two boxes for entry of the analogue output at zero flow and full scale appear.
These are numeric entries in the units and time base selected earlier.

analogue outputs
Atrato flow meter analogue outputs

View the complete Titan Flow Meters Range


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