How to Configure RevPi Gate for Modbus TCP Slave

Memory areas

Predefined memory areas are available for addressing the process data. Optionally, you can access the input and output data areas bit by bit (using coils) or word by word.

Modbus Address area	Use	Access	Access type	Meaning
1 – 256	Input Register	Read Only	Holding/Input *	Values that the other RevPi Gate supplies.
1025 – 1280	Output Register	Read/Write	Holding	Values that are supplied to the other RevPi Gate.
4097/0x1001	Gateway Status	Read Only	Holding	Displays the connection status to the other RevPi Gate.
				0x01	Initialisation, checking Hardware.
				0x02	Connection to the other gateway component is checked.
				0x03	Other gateway component detected.
				0x04	Communication to the other gateway component established.
4098/0x1002	Fieldbus status of the other gateway component	Read Only	Holding	0x00	Fieldbus not connected. Check all Connections.
				0x01	Fieldbus connected, no data communication. Check whether an IP address is set.
				0x02	Gateway component configured, no data communication.
				0x03	Cyclical data Exchange.
4099/0x1003	IP Address	Read/Write	Holding	IP Address High Word
4100/0x1004	IP Address	Read/Write	Holding	IP Address Low Word
4101/0x1005	Network Mask	Read/Write	Holding	Network Mask High Word
4102/0x1006	Network Mask	Read/Write	Holding	Network Mask Low Word
4103/0x1007	Gateway Address	Read/Write	Holding	Gateway Address High Word
4104/0x1008	Gateway Address	Read/Write	Holding	Gateway Address Low Word
4105/0x1009	Max. Number of Modbus/TCP connections	Read/Write	Holding	Shows the maximum number of Modbus/TCP connections that can exist simultaneously. Value Range: 2-20
4106/0x100a	Current number of Modbus/TCP connections	Read Only	Holding	Shows the current number of Modbus/TCP Connections.
4107/0x101b	Write Timeout	Read/Write	Holding	The write timeout function is active if there is a value > 0 in this Register. It specifies the time interval at which at least one of the output registers must be written As soon as the time has elapsed since the last write, all output registers are set to the default value 0.
4108/0x100c	Reset	Read/Write	Holding	Restarts the RevPi Gate if 0x4b42 is written here.

*Input and holding registers are not distinguished. They can be read via function code 0x04

Register area for bit by bit access

Address area	Use	Access	Access type	Meaning
1 – 3840	Input Bits (Coil)	Read Only	Holding/Input*	Values that the other gateway component supplies.
16385 – 20224	Output Bits (Coil)	Read/Write	Holding	Values that are supplied to the other gateway component.

*Input and Holding Register are not differentiated. They can be read using function code 0x004.

Functions

You can access the data area of the gateway component using the following functions:

Function code	Use	Description	Max. size per telegram
0x01	Read data bit by bit	read coils	2000 Bit
0x02	Read data bit by bit	read discrete inputs	2000 Bit
0x05	Write data bit by bit	write single coil	1 Bit
0x0f	Write data bit by bit	write multiple coils	1968 Bit
0x03	Read data word by word	read holding registers	125 words
0x04	Read data word by word	read input registers	125 words
0x06	Writedata word by word	write single register	123 words
0x10		write multiple registers
0x16		mask write register
0x17	Read and write data word by word	read/write multiple registers	Read 125 words Write 121 words