Toptech MultiLoad II User Manual

Chapter 1 – Protocol Specification
7
CHAPTER 1 PROTOCOL SPECIFICATION
The MultiLoad auto-detects four low level computer protocols for host communications.
- Smith Protocol
- Brooks Protocol
- Daniels
- Modbus-RTU Protocol
- Modbus- TCP/IP Protocol
Note: All unknown or not allowed signal or code sequences are rejected and have no impact on the
software or measurement data.
Host communication can occur via multi-dropped RS-232/RS-485 serial on COM 1 or Ethernet 10/100 socket
communication on port 7734. Port 7735 supports SSL encryption (TLS v1.2 only for security reasons) and can
be enabled via the network setup screen.
1.1 DEFINITIONS
The non-printing characters that form the skeleton of the Smith and Brooks protocols are standard ASCII
(American Standard Code Information Interchange):
ASCII CHARACTER
DECIMAL
HEX
BINARY
NUL
0
0
00000000
STX
2
2
00000010
ETX
3
3
00000011
SOH
1
1
00000001
PAD
127
7F
01111111
CHARACTER
DESCRIPTION
BCC
Block Check Characters. The ASCII hex representation of the binary sum of all
the data in the message from the SOH through the ETX character.
LRC
Longitudinal Redundancy Check. The LRC is an ASCII character computed as
the exclusive or (XOR) sum of all characters following the STX and including
the ETX.
CRC
Cyclic Redundancy Check.
A1..A3
A 3-character ASCII unit address of the MultiLoad. Please refer to the
MultiLoad User Guide for configuring the unit address.
D1..Dn
Data field characters.
Fn
Function field code.
Adr
A single character binary unit address of the MultiLoad.

Toptech MultiLoad II Specifications

General

Brand	Toptech
Model	MultiLoad II
Category	Control Systems
Language	English