Applied Motion ST10-Q-NE - Manual (Page 10)

10 920-0072 Rev E
9/9/2014
Modbus User Manual
IO Encoding Table
Useful ASCII values for IO commands. Character values shown are taken from standard SCL command
nomenclature. For example, a Feed to Sensor command example may utilize the falling edge of input 1 and
appear as FS1F. To encode this command the user would select 0x31 for the character ‘1’ and 0x46 for the
character ‘F’.
Character hex code
‘1’ 0x31 input 1 or output 1
‘2’ 0x32 input 2 or output 2
‘3’ 0x33 input 3 or output 3
‘4’ 0x34 input 4 or output 4
‘L’ 0x4C low state (closed)
‘H’ 0x48 high state (open)
‘R’ 0x52 rising edge
‘F’ 0x46 falling edge
Modbus/TCP Protocol
- Provides a Client/Server communication between devices connected on an Ethernet TCP/IP network.
- Communication via TCP to port 502.
- Headers are encoded in Big-endian.
- Application Data Unit (ADU) Header is 7 bytes long:
•
Transaction Identifier (2 bytes): Identification of a Modbus Request/Response transaction.
• Protocol Identifier (2 bytes): 0 = Modbus protocol.
• Length (2 bytes): Number of following bytes directly after this length field.
• Unit Identifier (1 byte): Identification of a remote slave connected on a serial line.
- Protocol Data Unit (PDU) is the Modbus/TCP equivalent of the Modbus/RTU message payload described
above.
- Note: Too much polling on port 7775 (UDP Port) may cause sluggish behavior (Q Programmer™ polls).
- TCP connection will timeout by default after 60 seconds of inactivity. This can be modified by a command
sent via UDP to port 7775. Command is 3 bytes with the third byte equal to the TCP timeout in seconds. A value
of 0 will disable the timeout. Changes to the TCP timeout will take place once the drive is reset.
Command Example (3 bytes): 0x00 0x1F 0x0A - sets TCP timeout to 10 seconds.
- Modbus register 40054-40055 is now Pulse Counter. Time Stamp has been deprecated.