Smith Protocol; Brooks Protocol; Daniels Protocol - Toptech MultiLoad II Manual

Chapter 1 – Protocol Specification
1.2 S P
MITH ROTOCOL
The Smith protocol is compatible with devices from Smith Meter, such as the Accuload I and Accuload II mini-
computer modes of operation. Using this protocol, MultiLoad accepts data in the format:
NUL
A1 and A2 are the last two digits of the unit address in the RCU configuration.
1.3 B P
ROOKS ROTOCOL
The Brooks protocol is compatible with devices from Brooks Instruments such as their Petrocount RAU™ and
IMS Control™ units running in computer mode. Using this protocol, MultiLoad accepts data in the format:
DESTINATION
SOH
A1
1.4 D P
ANIELS ROTOCOL
The Daniels protocol is compatible with devices from Daniels Flow Products. Using this protocol, MultiLoad
accepts and responds with data in the format:
Quiet
ADR
Time

Daniels protocol messages are framed by a quiet time of three and one-half characters.

ADR is binary character of the address of the MultiLoad. Typically 0x01.

Fn is expected to be 0x41/0x42 alternating on each command. Responses will have Fn as 0x41/0x42
for normal responses and 0xc1/0xc2 for exception responses.

D1...Dn is string data containing the commands listed in this manual.
Note: Modbus extension to return larger packet sizes: On messages with data packet sizes from 2 to 252
characters the Fn values of 0x41/0x42 will be returned. With messages outside this range, Fn will be the MSB
value of the data size and the Len will be LSB of the data size.
For Example:
Fn = 0x41, Len = 0x80, when data packet size = 0x0080,
Fn = 0x42, Len = 0x80, when data packet size = 0x0080,
Fn = 0x00, Len = 0xFF, when data packet size = 0x00FF ( 255),
Fn = 0x01, Len = 0x00, when data packet size = 0x0100 ( 256),
Fn = 0x01, Len = 0x01, when data packet size = 0x0101 ( 257),
Fn = 0x02, Len = 0x00, when data packet size = 0x0200 ( 512),
Fn = 0x04, Len = 0x00, when data packet size = 0x0400 (1024),
Fn = 0x08, Len = 0x00, when data packet size = 0x0800 (2048).
STX A1 A2
SOURCE
A2 A3 S1 S2
LEN
FN
(2 – 252)
data ETX
STX data ETX
S3
D1...DN CRC1
LRC PAD
BCC BCC
1 2
Quiet
CRC2
Time
8