Modbus

Modbus - Documentation

Common

The controller exposes a Modbus ‘Master’ at the specified TCP interface on port 502.

There are dedicated registers for the VFD, PIDs and internal values.

System Registers

Name	Component ID	Address	RW	Function Code	Value	Register Description
System	1	9	-W	0x6	1	Print Modbus Queue
System	1	9	-W	0x6	2	Print Component Modbus Registers
System	1	100	-W	0x6	1	Reset Controller
System	1	19	-W	0x6	1	Print PID controller states

Remarks

Implementation for these calls : short ModbusBridge::loop() ./ModbusBridge.cpp
It requires a USB cable connected, with 19200 bauds, 8 bits, no parity and 1 stop bit. You can use Arduino’s ‘Serial Monitor’ to see the output.

VFD Registers

The VFD (Omron - MX2) is being polled and controlled via RS485 at a defined Modbus slave address (Default 1). See more about the setup here.

Name	Component ID	Address	RW	Function Code	Value	Register Description
VFD	200	5	-W	0x6	1	Set VFD in `RUN` mode
VFD	200	5	-W	0x6	2	Set VFD in `STOP` mode
VFD	200	5	-W	0x6	3	Set VFD in `RETRACT` mode (stop and retract)
VFD	200	6	-W	0x6	0-100	VFD Target Frequency
VFD	200	2	-R	0x6	0-100	VFD Current Monitor
VFD	200	3	-R	0x6	-	VFD Status `OMRON_STATUS_STOPPED=2` `OMRON_STATUS_RUNNING=0`
VFD	200	4	-R	0x6	-	VFD State `OMRON_STATE_ACCELERATING=4` `OMRON_STATE_DECELERATING=2` `OMRON_STATE_RUNNING=3` `OMRON_STATE_STOPPED=1` `OMRON_STATE_ERROR=8`

PID Registers

The PID controllers (Omron - EDC5) are being polled and controlled via RS485 at a defined Modbus slave address, starting by default from 4.

Name	Component ID	Address	RW	Function Code	Value	Register Description
PID	100	20	R-	0x6	0-Maximum Temperature (`PV`)	PID-0 Temperature
PID	100	21	R-	0x6	0-Maximum Temperature / Set Point	PID-0 Set Point (`SP`)
PID	100	22	R-	0x6	Status	PID-0-Status / Default State : ‘Is Heating’
PID	100	23	R-	0x6	0-Maximum Temperature (`PV`)	PID-1 Temperature
PID	100	24	R-	0x6	0-Maximum Temperature / Set Point	PID-1 Set Point (`SP`)
PID	100	25	R-	0x6	Status	PID-1-Status / Default State : ‘Is Heating’

Auxillary Registers (Sensors / Switches)

Name	ID	Address	RW	Function Code	Number Addresses	Register Description
OmronPID	100	20	R-	0x6	6
MB_Relay	300	41	RW	1	1
MB_Relay	301	42	RW	1	1
POT	400	51	R-	3	1
POT	401	52	R-	3	1
Pos3Analog	501	61	R-	3	1	- Read Position : Address=61(3D) -> [Up:1 Middle:0 Down:2]
Pos3Analog	502	62	R-	3	1	- Read Position : Address=62(3E) -> [Up:1 Middle:0 Down:2]
VFD	200	5	–	3	1
Stepper	601	70	RW	-1	4
MotorLoad	210	2	R-	3	1
Status - LED	701	84	RW	3	1
Status - LED	702	85	RW	3	1

Stepper

Name	ID	Address	RW	Function Code	Value	Register Description
Stepper-0	601	70	RW	0x6	0-5000	Stepper-Speed
Stepper-0	601	71	RW	0x6	0-1	Stepper-Direction
Stepper-0	601	72	R-	0x6	-	Stepper-Status
Stepper-0	601	72	–	0x6	-	Stepper-User

Feed - Servo

Name	ID	Address	RW	Function Code	Value	Register Description
Feed - VFD - Ratio	601	16	-W	0x6	0-100	Stepper-Speed

The servo is turned on automatically as soon the VFD starts running.

Tools

To monitor and control the system, please open printhead-poll.mbp with MbPoll_v9.4.0.exe

Google Sheet

Simulate Modbus for Development

Please use MbSlave_v7.3.0.exe to start a Modbus-RTU master on TCP. You can use the ModbusPoll app to verify your code.

References

Modbus Poll Registers - 0 to 100 - GoogleSheet
Omron - E5DC Documentation
Omron - E5DC Communication Documentation
Omron - MX2 Documentation
Related Files
- modbus-connect.png (35 KB)
- modbus-run-test.png (31 KB)
- modbus-test.jpg (1 MB)
- mpoll-registers.jpg (22 KB)
Related Documents
- mpoll-registers.pdf (185 KB)
- MX2-Coils.pdf (23 KB)
- MX2-HoldingRegisters.pdf (158 KB)
- pid-regs-edc5.pdf (192 KB)

Modbus - VFD Control

VFD

Start & Stop

Starts or stops the VFD, be aware that a target frequency has to be set as well

Address : 5
Function : 6 (WRITE_REGISTER)
Values :
- On : 1
- Off : 2

TCP Sequence for Start

d2 8d 00 00 00 06 01 06 00 05 00 01
                   +  +  +    +
                   |  |  |    |
                   |  |  |    +----> Value (2 bytes) = 00 01
                   |  |  |
                   |  |  +----> Address (2 bytes) = 05 or 0x0005
                   |  |
                   |  +--> Function Code (Always 6)
                   |
                   +--> Slave - ID (Always 1)

TCP Sequence for Stop

d2 8d 00 00 00 06 01 06 00 05 00 02
                   +  +  +    +
                   |  |  |    |
                   |  |  |    +----> Value (2 bytes) = 00 02
                   |  |  |
                   |  |  +----> Address (2 bytes) = 05 or 0x0005
                   |  |
                   |  +--> Function Code (Always 6)
                   |
                   +--> Slave - ID (Always 1)

Frequency

Sets the target frequency

Address : 6
Function : 6 (WRITE_REGISTER)
Values : 1 - 50

TCP Sequence for setting target frequency to 50 Hz

Remark : Please respect the max. main frequency setting on the inverter (settings)

d2 8d 00 00 00 06 01 06 00 05 00 32
                   +  +  +    +
                   |  |  |    |
                   |  |  |    +----> Value (2 bytes) = 00 32 (for 50Hz)
                   |  |  |
                   |  |  +----> Address (2 bytes) = 06 or 0x0006
                   |  |
                   |  +--> Function Code (Always 6)
                   |
                   +--> Slave - ID (Always 1)

Direction

Sets the rotation

Address : 7
Function : 6 (WRITE_REGISTER)
Values :
- Forward : 1
- Reverse : 2
- Stop : 3

TCP Sequence for setting direction : Forward

d2 8d 00 00 00 06 01 06 00 07 00 01
                   +  +  +    +
                   |  |  |    |
                   |  |  |    +----> Value (2 bytes) = 00 01
                   |  |  |
                   |  |  +----> Address (2 bytes) = 07 or 0x0006
                   |  |
                   |  +--> Function Code (Always 6)
                   |
                   +--> Slave - ID (Always 1)

TCP Sequence for setting direction : Reverse

d2 8d 00 00 00 06 01 06 00 07 00 02
                   +  +  +    +
                   |  |  |    |
                   |  |  |    +----> Value (2 bytes) = 00 02
                   |  |  |
                   |  |  +----> Address (2 bytes) = 07 or 0x0006
                   |  |
                   |  +--> Function Code (Always 6)
                   |
                   +--> Slave - ID (Always 1)

Modbus - PID Control

PID Controllers

The PID controller target temperatures can be set as follows:

PID 1 : Address 10
PID 2 : Address 11
PID 3 : Address 12

Set Target temperature on PID 1 to 100Degc

Address : 10 (0x10)
Function : 6 (WRITE_REGISTER)
Values : 0 - Max Temperature (280)

TCP Sequence

d2 8d 00 00 00 06 01 06 00 0A 00 10
                   +  +  +    +
                   |  |  |    |
                   |  |  |    +----> Value (2 bytes) = 00 10 (16 Degc)
                   |  |  |
                   |  |  +----> Address (2 bytes) = 20 or 0x0014
                   |  |
                   |  +--> Function Code (Always 6)
                   |
                   +--> Slave - ID (Always 1)

Set Target temperature on PID 2to 100Degc

Address : 11 (0x0B)
Function : 6 (WRITE_REGISTER)
Values : 0 - Max Temperature (300)

TCP Sequence

d2 8d 00 00 00 06 01 06 00 0B 00 10
                   +  +  +    +
                   |  |  |    |
                   |  |  |    +----> Value (2 bytes) = 00 64 (100 Degc)
                   |  |  |
                   |  |  +----> Address (2 bytes) = 18 or 0x000B
                   |  |
                   |  +--> Function Code (Always 6)
                   |
                   +--> Slave - ID (Always 1)

Set Target temperature on PID 3 to 100Degc

Address : 12 (0x0C)
Function : 6 (WRITE_REGISTER)
Values : 0 - Max Temperature (300)

TCP Sequence

d2 8d 00 00 00 06 01 06 00 0C 00 10
                   +  +  +    +
                   |  |  |    |
                   |  |  |    +----> Value (2 bytes) = 00 10 (16 Degc)
                   |  |  |
                   |  |  +----> Address (2 bytes) = 0C or 0x000C
                   |  |
                   |  +--> Function Code (Always 6)
                   |
                   +--> Slave - ID (Always 1)

Testing with Modbus Poll

Testing with Hercules

Modbus - Errors

Error Codes

The system exposes the current error code as a Modbus register at address 0x00 (FunctionCode:0x3) :

E_VFD_TIMEOUT = 1002
E_PID_TIMEOUT = 2002
E_FEED_OVERLOAD = 4001
E_VFD_OVERLOAD = 1001

System Debug Commands

Name	Component ID	Address	RW	Function Code	Value	Register Description
System	1	9	-W	0x6	1	Print Modbus Queue
System	1	9	-W	0x6	2	Print Component Modbus Registers
System	1	100	-W	0x6	1	Reset Controller
System	1	19	-W	0x6	1	Print PID controller states

See more details in the PHApp::onError Implementation

Modbus

Modbus - Documentation

Common

System Registers

VFD Registers

PID Registers

Auxillary Registers (Sensors / Switches)

Stepper

Feed - Servo

Tools

Simulate Modbus for Development

References

Subsections of Modbus

Modbus - VFD Control

VFD

Start & Stop

Frequency

Direction

Modbus - PID Control

PID Controllers

Set Target temperature on PID 1 to 100Degc

Set Target temperature on PID 2to 100Degc

Set Target temperature on PID 3 to 100Degc

Testing with Modbus Poll

Testing with Hercules

Modbus - Errors

Error Codes

System Debug Commands