Pioneer FlowMeter Program
Written by Ben Nabors, Patrick McDonagh
Hardware Used
- PLC: Micro820 [2080-LC20-20QBB]
- Slot 1: 2080-IF2
Inputs
Digital Inputs
| Input | Usage |
|---|---|
| 0 | Flowmeter Type (On = Modbus) |
Analog Inputs
| Input | Usage |
|---|---|
| 0 | 4-20mA Flowmeter |
| 1 | 4-20mA Pressure |
Outputs
Digital Outputs
| Output | Usage |
|---|---|
| 0 | Analog Flowmeter in use |
| 1 | Modbus Flowmeter in use |
Configuration
The system can be configured to use either an Analog Flowmeter or a Modbus Flowmeter. The system defaults to the Analog Flowmeter.
To enable the modbus flowmeter do one of the following:
- Jumper 24VDC to Digital Input 0
- Write 1/True to the tag "sw_UseModbusFlowmeter" from SCADA
To enable the analog flowmeter do BOTH of the following:
- Remove the 24VDC jumper from Digital Input 0
- Write 0/False to the tag "sw_UseModbusFlowmeter" from SCADA
When the system is configured to use the Analog Flowmeter, Digital Output 0 will be ON.
When the system is configured to use the Modbus Flowmeter, Digital Output 1 will be ON.
Customizing Modbus Parameters
The system defaults for modbus parameters enable communication with the Flexsim meters. The following tags can be modified to enable communication with different device types:
| Tag | Default | Usage |
|---|---|---|
| cfg_Flowmeter_ModbusNode | 1 | Node Address of Flowmeter |
| cfg_FlowTotalPos_Register | 10133 | Register of Positive Flow Total |
| cfg_FlowTotalNeg_Register | 10149 | Register of Negative Flow Total |
| cfg_FlowGross_Register | 10117 | Register of Gross Flow Rate |
The serial port is configured as a Master for Modbus RTU over RS485 with baud rate of 9600, 8E1.
SCADA Tags
The following tags would be relevant to read over SCADA:
| Tag | Type | Description | Access |
|---|---|---|---|
| val_FlowTotalPos | REAL | Positive Flow Total | R |
| val_FlowTotalNeg | REAL | Negative Flow Total | R |
| val_FlowGross | REAL | Gross Flow Rate | R |
| val_Pressure | REAL | Pressure Reading | R |
| val_AI00_uA | REAL | uA Reading on AI00 | R |
| val_AI01_uA | REAL | uA Reading on AI01 | R |
| Flow_EU_Max | REAL | EU Max Flow Scaling | RW |
| Flow_EU_Min | REAL | EU Min Flow Scaling | RW |
| Pressure_EU_Max | REAL | EU Max Pressure Scaling | RW |
| Pressure_EU_Min | REAL | EU Min Pressure Scaling | RW |
| cmd_ClearFlowTotal | BOOL | Clear analog Flow Total Command | RW |
| sw_UseModbusFlowmeter | BOOL | Use the modbus flowmeter | RW |
| use_ModbusFlowmeter | BOOL | Status of using Modbus Flowmeter | R |