Weighing Transmitter Selection: MV-WI0014 Analog Output or MV-WI0015 RS232?

Weighing transmitter selection should start at the load-cell input. A transmitter with the desired output can still be unsuitable if it cannot excite the connected bridges or resolve the required weight change. METRAVON MV-WI0014 and MV-WI0015 illustrate why an analog output and a digital interface need different checks rather than a shared list of assumed features.

Weighing transmitter selection: two different signal routes

The published drive capability for both models is one 350-ohm analog sensor. Connecting four nominal 350-ohm bridges in parallel produces an 87.5-ohm input load, not a single 350-ohm load. A passive junction box combines connections; it does not provide the extra excitation capacity. Use an instrument designed for the actual bridge load when several cells must be combined.

Obtain the load cell's input resistance, rated sensitivity, required excitation and wiring details. Also state gross capacity, tare and the smallest weight increment that matters. If those inputs are unknown, selecting from output labels alone is premature.

Check the analog route against the required result

The MV-WI0014 data specify an 8-30 VDC supply, 5 V sensor excitation and a sensor sensitivity range of 1-3 mV/V. The external output load is listed as 0-500 ohms, with reduced load capability below 10 VDC supply. Include the receiving input and other series resistance when assessing the proposed circuit.

The catalogue also lists 1% linearity. Do not describe this transmitter as a high-precision solution merely because the connected load cell has a much smaller quoted error. Confirm how the linearity specification is defined and whether the total transmitter-and-PLC error is acceptable over the intended working range.

For an explicitly configured example, 4-20 mA mapped to 0-100 kg gives 0.16 mA per kilogram. A 0.1 kg change corresponds to 16 microamps. That calculation is only the ideal conversion slope. It does not show that this transmitter and a particular PLC input can resolve or measure 0.1 kg reliably.

Check the receiving input's range, resolution and error, then test the complete conversion at several applied loads. Define whether the current represents gross or net weight and where tare is applied. Do not apply an undocumented second scaling correction in the HMI to compensate for a mismatch upstream.

Digital does not mean Modbus

MV-WI0015 documentation lists RS232, 9600 bit/s, eight data bits without parity and command-based reading and configuration. Obtain the full command specification, including message framing and any parameters not stated in the catalogue, before developing the host connection.

There are two documented supply versions: 5 V with a 5-8 V range, or 9 V with a 9-12 V range. These are alternatives, not one continuous 5-12 V input specification. Specify the version on the order and check the installed supply before connection.

No native RS485 or Modbus RTU capability is established by those data. An RS232-to-RS485 electrical converter alone does not translate a proprietary command set into Modbus. If a PLC requires Modbus RTU, confirm a complete supported conversion arrangement or select a device documented for that protocol.

Specify response and faults before writing control logic

The catalogue details cited here do not establish an end-to-end update time, isolation rating or a defined output for every sensor fault. Request those details when they affect the process. Do not assign an assumed fault current or timeout behavior to either model.

For batching, test the time between a load change and the value used by the controller with the intended filtering enabled. For serial acquisition, define how the host detects a missing or invalid reply. For an analog input, verify which faults the receiving circuit can actually distinguish. A number inside the normal range is not, by itself, proof of a healthy measurement.

Use the final wiring and receiving equipment for commissioning. Apply a suitable reference, compare input and output, inspect PLC engineering units and exercise an approved loss-of-signal test. The PLC signal-chain guide covers the wider integration checks.

Questions that determine the order

Q1. Can MV-WI0014 read a cell rated at 0.5 mV/V?

That sensitivity is below the published 1-3 mV/V range. Do not assume span adjustment will make it compatible. Request confirmation for the exact sensor or choose a transmitter with a documented input range that covers it.

Q2. Does MV-WI0015 accept a digital load cell?

The documented input is one 350-ohm analog sensor. The digital description refers to the transmitter's data interface; it does not establish compatibility with a digital load-cell network.

Q3. Is an analog output included with MV-WI0015?

The documentation identifies 4-20 mA as optional. Specify the needed output and obtain confirmation of the delivered version, terminals and operating details. A catalogue option should not be treated as fitted hardware.

Q4. What should be included in a price request?

Provide the cell datasheet and quantity, supply voltage, output destination, working weight range, smallest required change and response requirement. State whether calibration and integration are included. Send these through the METRAVON transmitter enquiry so the quotation identifies a compatible configuration rather than only a model name.

Summary

MV-WI0014 and MV-WI0015 have specific single-cell input limits and different output arrangements. Check those limits before evaluating convenience or price. Accept the selected transmitter by testing the required weight result at the actual receiving system, with faults and configuration recorded.