Hanna Instruments HI520 - Modbus Remote Control; Modbus Wiring; Operating Modes When Using Modbus

Modbus Remote Control 158
25. MODBUS REMOTE CONTROL
Modbus is a request / response software protocol implemented on HI520 and intended for efficient and immediate
remote industrial process control.
25.1. MODBUS WIRING
Follow the lead markings (+ positive / – negative) to ensure that output leads are correctly wired to the
COMM position (Terminal 2) on the main board.
COMM
-
B A +
IN1 IN2 A01 A02 A03 A04
PROBE 2
-
B A +
PROBE 1
-
B A +
Terminal 1
Terminal 2
Note: See 4.2 Wiring for full wiring details
25.2. OPERATING MODES WHEN USING MODBUS
Mode Type Scope Description
Manual
Local control, controller
operated manually
Controller operated manually.
Note: Remote Control is not available.
Local Edit Local edit of settings & parameters
Local edit of controller’s settings and parameters.
Note: Remote Control is not available.
Calibration System calibration
Allows for controller’s system calibration.
Note: Remote Control is not available.
Remote Control HI520 remote control mode
Remote operation is available.
When not enabled, controller reverts to manual mode.
Remote View View parameter & settings values
Remote Control Mode must be enabled.
Use Modbus function codes to view or retrieve data.
Note: Parameters cannot be updated in this mode.