|Modbus Protocol Type
||Choose Modbus Protocol Type
||Binary message format. 8 bits per data byte.|
||ASCII message format. 16 bits per data byte.|
||Use Modbus/TCP message format.|
|Modbus Protocol Mode
||Choose Modbus Protocol Mode
||IOServer wil initiate all requests.|
||IOServer will wait for and respond to requests. The slave can process requests from multiple masters at the same time.|
||Maximum of frame. 256 is the standard maximum frame size.|
||The initial command sent to the device to check if the device is online. In the form "BitAddress, Function Code, BitCount". The default value is "0,3,16".
|Function Code||Modbus Address||Data Type|
||Device address of slave.|
|Register Address Size
||Size of each register in the PLC. The default is two bytes per register location.|
|Non standard 1 origin addressing
||Add 1 to address when requesting data.|
||Treat all integers as signed.|
|0 Origin addressing for bits in Registers.
||Bits in registers are numbered 0 to 15. The default numbering is 1-16.|
|Reverse Bits in Registers
||The bits numbering in registers are reversed|
|32 Bits Value Byte Ordering
||Long value (4 bytes) byte ordering of device.
Device.40001,I4 will read the two registers at 40001 as a 32 bit signed integer value.
|32 Bits Floating Point Byte Ordering
||Single Precision Floating point numbers byte ordering of device.
Device.40001,R4 will read the two registers at 4001 as a 32 bit floating point value.
|64 Bits Floating Point Byte Ordering
||Double Precision Floating point numbers byte ordering of device.|
Modbus Channel Master Mode
||Master Mode, issue read and write function codes to slave|
||Issue write function code to slave, accept write function code from slave|
|n Seconds (1 to 254)
||Issue read function code to slave for next n seconds, issue write function code to slave, accept write function from slave|
Modbus Channel Slave Mode
||Slave Mode, accept read and write function codes from master|
||Accept read and write function codes from master|
||Accept read and write function codes from master, issue write function code to slave|
Modbus Function Codes Supported
1, 2, 3, 4, 5, 6, 7, 15 and 16
Simulating Modbus Slave error
Writing a value with its 7th bit set to .E (Exception Status) in a Modbus Slave will cause it to response with that exception code to all requests. A value of 255 will stop it from responding.
Enron/Daniels Modbus Settings
Enron/Daniels Modbus Settings in IOServer
Register Address Size: 2 Bytes
Non standard 1 origin addressing
32 Bits Value Byte Ordering: Swap bytes and words
32 Bits Floating Point Byte Ordering: Swap bytes and words
|| 16 bit Short integer|
|| 32 bit Long integer|
|| 32 bit Floating point|
When the Register Address size is set to 2 bytes, each 32 bits value occupies two register locations and their addresses must be odd.
When the Register Address size is set to 4 bytes, each 32 bit value occupies one register location. One device is configured with 4 bytes addressing to access the 32 bit values and second device with 2 bytes addressing to access the boolean and 16 bit values.
SMA Data Manager Settings
Use "480000,4,32" for initialization and Modbus Device.Non-standard 1 origin addressing set.
Q:How do I access the two 16 bits registers at Device.40011 and Device.40012 as an IEE754 32-bit floating-point value.
A:Use the following tag syntax:
See addtags for other data types.
Please make sure that the Modbus Device.32 Bits Floating Point Byte Ordering option is correct for your device.
IOServer running on a Pentium 4, 2.8 GHz PC under Windows 2000 Advanced Server reading from a remote device.
|Protocol||Requests per second|
|TCP/IP, 2 bytes per request
|TCP/IP, 250 bytes per request
|TCP/IP, 1450 bytes per request