Overview
All eGauge models with firmware v3.2 or higher have Modbus TCP output capability. eGauge models with USB ports also have capability for Modbus RTU (serial via RS485) output capability, with use of the eGauge USB485 converter. The Modbus server can be enabled in Settings → Modbus Server. If the Modbus Server option is not available, upgrade your firmware in Tools → Firmware Upgrade.
Firmware version notice
It is recommended to upgrade your eGauge to the most recent firmware version before enabling the Modbus Server for the first time.
Prior to firmware v4.0, the Modbus map addresses are liable to change if the register name or contents is modified. Firmware v4.0 adds additional ranges that are tied to the register ID. The addresses used prior to v4.0 are still usable to provide backwards-compatibility, but are marked as deprecated and are not recommended to use as installation settings reconfiguration may change them.
Prerequisites
- Modbus RTU with an EG4xxx model eGauge, the RS485/USB adapter is needed.
- Modbus TCP requires that the eGauge and the device communicating with it have visibility to one another on the same LAN.
Instructions
Step 1: Log into the eGauge meter interface and navigate to: Setup → Other Settings from the Main Menu.
Step 2: Choose Modbus Server at the left. The following options are available:
Step 3: Fill in the correct settings for your installation. You may need to coordinate with the IT administrator to get the correct settings to be compatible with the existing network. Settings and options are outlined below:
- Modbus unit ID for this device: Fill in the unique Modbus Unit ID that will identify the eGauge on the Modbus network. You may need to contact the network administrator for this information.
- Enable Modbus TCP server: Enable this option to read values from the eGauge via Modbus TCP.
- TCP port to listen on: Defaults to 502 and is configurable. Check with network administration before changing this value.
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Enable Modbus RTU server: Enable this option to read values from the eGauge via Modbus RTU. Complete serial settings to be compatible with any other Modbus device on the same string:
- In the first field, choose the RS485/USB adapter from one of the eGauge USB ports.
- Select a baud rate, parity and stop bits. All devices on the same Modbus RTU string must be set to the same serial settings.
Viewing the eGauge Modbus Map
The buttons at the top of the Modbus Server settings page can be used to view or export a .CSV file of the eGauge meter Modbus map.
The Modbus map defines the available data points on each eGauge meter. Note that the map is based on the individual meter configuration and can vary between meters with different register configuration settings in place.
Information in the Modbus map will be needed to configure settings on the device intended to read Modbus registers from the eGauge.
Registers marked as deprecated should not be used in new installations and are only present for backward compatibility.
Troubleshooting and Tips
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Issue: I'm getting errors when trying to read from the eGauge.
- Solution: When making requests from another system the 30,000 prefix should be dropped from the register addresses.
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Issue: Requests to the eGauge are timing out.
- Solution: check wiring for any loose connections
Additional Resources