Numeric MQTT data points do not have an evidenced one-step multiplier-and-offset calculator equivalent to the referenced Modbus function. The available workaround is to retain the MQTT value as a raw point and apply scaling through a Meta Point, subject to verification on the target system.
Current MQTT Scaling Constraint
The evidence requests native scaling for numeric MQTT data points and reports that no implementation plans are known. This is not an official roadmap commitment, and no product name, software version, or firmware revision is provided; confirm current capability through the manufacturer’s official documentation or support channel before designing around this limitation.
Two-Point Scaling Architecture
Use the MQTT data point as the unmodified input and a Meta Point as the calculated engineering-value output. Where the required conversion follows the referenced multiplier-and-offset model, define it symbolically as:
scaled_value = raw_mqtt_value * multiplier + offsetThe evidence does not identify Meta Point syntax, configuration fields, data types, or update behavior. Map the symbolic terms to the controls available in the installed software instead of assuming particular identifiers.
Configuration and Verification
- Configure the numeric MQTT data point to expose the received raw value without applying an undocumented conversion.
- Create a Meta Point that reads the raw MQTT point and applies the required multiplier and offset.
- Compare the Meta Point output against independently calculated results using known raw inputs. Also verify behavior when the MQTT value changes and when source data is unavailable, because update and invalid-data handling are not specified in the evidence.
Keep both points clearly distinguished: use the raw point for communications diagnostics and the Meta Point for the scaled engineering value. Native one-step MQTT scaling remains an unconfirmed future capability.
FAQ
Can a numeric MQTT data point apply a multiplier and offset directly?
The evidence does not establish a native one-step MQTT scaling function. Verify the installed software version, but plan on a Meta Point workaround unless official documentation confirms otherwise.
How do I scale an MQTT value with a Meta Point?
Retain the MQTT value as a raw numeric point, then calculate scaled_value = raw_mqtt_value * multiplier + offset in a Meta Point. Use the exact expression syntax supported by the target software.
How do I verify MQTT data point scaling?
Apply known raw inputs, calculate the expected result independently, and compare it with the Meta Point output. Verify value updates and unavailable-source behavior separately because those behaviors are not specified by the evidence.