6-Digit Process Meter & Flow Totalizer

Rate, analog square root, batch control, time based on rate from 0-1 mA, 4-20 mA or 0-10 V signals.
Ideal as a Flow Rate Meter & Totalizing Flow Indicator.

Analog signal totalizer meter


  • 6-digit display of rate or totalized rate, field scalable
  • 0-1 mA, 4-20 mA, 0-10V analog input
  • High accuracy: ±0.005% of span ±1 count
  • Extracts square root from differential pressure flow transducers
  • Universal 85-264 Vac / 90-300 Vdc or 10-48 Vdc / 12-32 Vac power
  • Transducer excitation output (isolated)
  • Wide choice of options:
    - 2 or 4 relays, mechanical or solid state (isolated)
    - 1 or 2 analog outputs (isolated)
    - Serial data I/O: Ethernet, USB, RS485, RS232 (isolated)
    - Custom curve linearization, time based on rate, batch control
Six-Digit Process Meter & Flow Totalizer by TD Micronic

Standard Counter Version

  • Six-digit display of rate or total at the push of a front panel key. A with the Standard counter main board and a VF voltage-to-frequency signal conditioner board can be scaled to display rate or totalized rate to six digits for 0-1 mA, 4-20 mA or 0-10V analog process signals. Special input ranges are available from the factory. For example, the display can be scaled to show flow rate in gallons/minute or liters/sec, or to show volume in gallons or liters from the 0-10V output of a flow transducer. Or the display can be scaled to display power consumption in kilowatts or total utilized energy in kilowatt-hours based on the 0-1 mA output of a watt transducer.
  • Square root extraction is selectable and can be applied to rate or total. This makes the VF ideal for use with differential pressure flow meters, which have a squared output. Totalized volume is based on linearized rate.
  • Accuracy is one of the highest for any digital panel meter: ±0.005% of span ±1 count.

Extended Counter Version

  • Batch control based on linearized total. A VF meter with the Extended counter main board can totalize linearized flow from an analog rate signal, and also count up to a preset value, or count down to zero from a preset value for batch control. Operation as a batch controller requires the dual-relay output board option. One of the relays is dedicated to ON/OFF batch control. The other relay is available to slow down rate near the setpoint or to provide another alarm or control function based on rate or total.
  • Custom Curve Linearization. For custom curve linearization, up to 180 data points can be input into a spreadsheet or text file by the user. The computer then calculates spline-fit segments, which are downloaded into the meter via RS232. The Extended VF meter can linearize and display analog inputs based on a custom curve, for instance to read out the volume of an irregularly shaped tank based on level or pressure, or to linearize a nonlinear transducer. Custom-linearized rates can also be totalized and be used for batch control.
  • Time Based on Rate. The Extended VF meter can display a time inversely proportional to measured rate, such as the time that it will take a conveyor to traverse an oven. As the rate of the conveyor is increased, the displayed baking time is decreased.

Principles of V-to-F Operation

Voltage-to-frequency signal conditioner boardThe V-to-F signal conditioner board converts the full-scale 0-1 mA, 4-20 mA or 0-10 V analog signal to a frequency of 10 kHz to 110 kHz. This frequency is determined by measuring period over a selected gate time (from 10 ms to 200 s) and taking the inverse of period. Selecting a short gate time provides a much higher update rate than conventional counting-type frequency meters. At the lowest frequency of 10 kHz and the minimum gate time of 10 ms, the meter is capable of 25 updates per second. Scaling to rate in engineering units and totalizing are done mathematically. Totals are calculated as the product of rate and time in seconds regardless of the selected gate time. Totals are stored in nonvolatile memory in case of power loss.

High Resolution Display

The display of rate or total may be scaled to ±999,999. The two least-significant digits may be set to display zero with rounding or be active digits. Noise in rate readings can be reduced by selecting a longer gate time. In addition, an adaptive digital filter can reduce variations due to noise while rapidly responding to actual changes in signal level.

Hardware Features

Optional plug-in boards for communications and control include Ethernet and other serial communication boards, dual or quad relay boards, and single or dual isolated analog output boards. s may be powered from 85-264 Vac or optionally from 12-32 Vac or 10-48 Vdc. The display is available with red or green LEDs. The 1/8 DIN case meets NEMA 4X (IP65) specifications from the front when panel mounted. Any setup functions and front panel keys can.

Readout 6 LED digits, 7-segment, 14.2 mm (.56")
Color Red or green LED
Range -999999 to +999999
Indicators Four LED lamps
Standard signal levels 4-20 mA, 0-1 mA, 0-10V (jumper selectable)
Input resistance 50Ω at 4-20 mA, 1.00 kΩ at 0-1 mA, 1.01 MΩ at 0-10V
Other signal levels Consult factory
Frequency Technique Inverse period
Update Rate Gate time + 30 ms (max)
Gate Time Selectable 10 ms to 199.99 s
Span tempco ±0.003% reading/°C
Zero tempco ±0.003% FS/°C
Accuracy at 25°C ±0.01% FS ± 1 count
Voltage, standard 85-264 Vac or 90-300 Vdc
Voltage, optional 12-32 Vac or 10-48 Vdc
Frequency DC or 47-63 Hz
Power  consumption (typical, base meter) 1.2W @ 120 Vac, 1.5W @ 240 Vac, 1.3W @ 10 Vdc, 1.4W @ 20 Vdc, 1.55W @ 30 Vdc, 1.8W @ 40 Vdc, 2.15W @ 48 Vdc
Power Isolation 250V rms working, 2.3 kV rms per 1 min test
Excitation Output (standard)
5 Vdc 5 Vdc ± 5%, 100 mA
10 Vdc 10 Vdc ± 5%, 120 mA
24 Vdc 24 Vdc ± 5%, 50 mA
Output Isolation 50 Vdc to meter ground
Analog Output (optional)
Output levels 4-20 mA, 0-20 mA, 0-10V, -10 to +10V (single-output option)
  4-20 mA, 0-20 mA, 0-10V (dual-output option)
Current compliance 2 mA at 10V ( > 5 kΩ load)
Voltage compliance 12V at 20 mA (< 600Ω load)
Scaling Zero and full scale adjustable from -99999 to +99999
Resolution 16 bits (0.0015% of full scale)
Isolation 250V rms working, 2.3 kV rms per 1 min test
  (dual analog outputs share the same ground)
Relay Outputs (optional)
Relay types 2 Form C contact relays or 4 Form A contact relays (NO) 2 or 4 Form A, AC/DC solid state relays (NO)
Current Ratings 8A at 250 Vac or 24 Vdc for contact relays 120 mA at 140 Vac or 180 Vdc for solid state relays
Output common Isolated commons for dual relays or each pair of quad relays
Isolation 250V rms working, 2.3 kV rms per 1 min tes
Serial Data I/O (optional)
Board selections RS232, RS485 (dual RJ11 or RJ45 connectors), USB, Ethernet, USB-to-RS485 converter, Ethernet-to-RS485 converter
Protocols Modbus RTU, Modbus ASCII, Modbus TCP (Ethernet), TDM ASCII
Data rates 300 to 19200 baud
Digital addresses 247 (Modbus), 31 (TDM ASCII),
Isolation 250V rms working, 2.3 kV rms per 1 min test
Operating temperature 0°C to 55°C
Storage temperature. -40°C to 85°C
Relative humidity 95% at 40°C, non-condensing
Protection NEMA-4X (IP-65) when panel mounted
Electrical Connections
Explanation Diagram for v-to-f Signal Connection
Flow from a Differential Pressure Transducer
Flow rate or volume from a differential pressure transducer An ideal application for the Standard VF meter: readout of flow based on the 4-20 mA analog signal from a differential pressure transducer. Options include dual relays for alarm or control, isolated analog output to turn the meter into a transmitter, and RS232/485 data communications.s
Up- or Down-Counting Batch Controller
Up or down counting batch controller An ideal application for the Extended VF meter: up- or down-counting batch controller. The dual-relay card is required. One relay is dedicated to batch control, the other relay is available to alarm the rate or total. The signal input can be linear or nonlinear. The display can be toggled between rate and total.
Volume of an Irregularly-Shaped Tank
Volume from an irregularly shaped tank The Extended VF meter can linearize analog signals for display and alarm using custom curve linearization with multiple nonlinear segments. As illustrated, tank level is measured by an ultrasound detector, which transmits a 4-20 mA signal. This signal is then converted to a highly accurate volume reading. Linearized readings can also be totalized.
Process Time from an Analog Rate Signal
A unique application of the Extended VF meter is displaying process time based on the 4-20 mA or 0-10 V signal from a rate meter. In this example, a tachometer transmits the speed of a conveyer belt through an oven. The meter displays baking time in the oven using the mathematical relationship time = distance / speed.

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