Metra Flow Meter – Instructions (5) External Connections

aggressive chemical flow meter system
External connections of the Metraflow ultrasonic flow meter, the perfect aggressive chemical flow meter system
aggressive chemical flowmeter pincs
“Each of the PIN Assignments can be adjusted as either and input or an output function. The operation to modify PIN 6, PIN 7 and PIN 8 are identical within the software, with the exception of the type of transistor pulse output. PIN 6 and PIN 8 are both NPN, whilst PIN 7 is a PNP type.
The options for each PIN (or wire), are: Not Used Input or Output
aggressive chemical flowmeter non used pins
Not used: The assigned PIN / WIRE is unused.
aggressive chemical flow sensor inputs
Input: Select this checkbox to use the PIN assigned as a TTL digital input for remote control, either for Resetting the Total Count or Resetting an Alarm

Notes on using electrical inputs on the Metraflow Meter

PIN 6 & 8: In input mode, the NPN (NFET) open drain output is disabled, and the input pin responds to an external input voltage which may be in the range of 0V to 30V. The logic threshold is at 2V so this input can be driven directly from a logic signal at TTL levels or CMOS at 3.3V or 5.0V levels. Alternatively, if this input is provided by a switch, then an example circuit is given below:

electrical inputs: of the Metraflow

PIN 7: In input mode, the PNP (PFET) open drain output is disabled, and the input pin responds to an external input voltage which may be in the range of 0V to 30V. The logic threshold is at 2V so this input can be driven directly from a logic signal at TTL levels or CMOS at 3.3V or 5.0V levels. Warning: because of the potential for conflict should the PNP output be activated accidentally, Titan Enterprises Ltd recommend a series resistor and Zener be fitted to safeguard any connected circuitry operating at logic levels. Alternatively, if this input is provided by a switch, then an example circuit is given below:

aggressive chemical flow metering

WARNING:
INCORRECT ELECTRICAL INSTALLATION CAN CAUSE DAMAGE TO USERS ELECTRONICS

Metraflow aggressive fluid flow meter
Output: Select this check box to use the PIN assigned as a PULSE; FLOW ALARM (SINGLE OR DUAL) or REVERSE FLOW output signal.
Pulse: The Metraflow has two options for Pulse output configuration depending on which PIN (Wire colour), is chosen. PIN 6/Yellow and PIN 8/Grey are both NPN pulse outputs; whilst PIN 7 is a PNP.

Metraflow Pulse Per

PULSE per: 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 10 kHz. So care must be taken to ensure that this pulse rate is not exceeded.

E.g. 5 L/Min at 10 Kilohertz equals (10,000 x 60)/5 = 120,000.Therefore 120,000 pulses per litre is the maximum resolution for 5 litres per minute assuming maximum frequency output. If the meter is being used up to 1 L/Min the pulse output and so resolution could be increased to five times this, 600,000P/L.

It is possible to send a test signal at varying Hz for each of the pulse output PIN/Wires. Clicking T opens a menu where you can choose a rate of Hz of pulse outputs which will be automatically sent for approximately 30 seconds.

NOTE: ABOVE 1KHZ IT IS RECOMMENDED THAT THE SYSTEM WIRING IS REVIEWED TO ENSURE IT IS ADEQUATE FOR THE SAMPLING RATE.