User manual for - TIMER SLC-94
9.
THE MODBUS PROTOCOL HANDLING
Transmission parameters:
1 start bit, 8 data bits, 1 stop bit, no parity control
Baud rate:
selectable from: 1200 to 115200 bits/second
Transmission protocol:
MODBUS RTU compatible
The device parameters and measurement result are available via RS-485 interface, as
HOLDING-type registers of Modbus RTU protocol. The registers (or groups of the registers)
can be read by 03h function, and wrote by 06h (single registers) or 10h (group of the registers)
accordingly to Modbus RTU specification. Maximum group size for 03h and 10h functions can
not exceeds 5 registers (for single frame).
The device interprets the broadcast messages, but then do not sends the answers.
Device also reads and processes BROADCAST queries, but then do not send any
answers.
9.1.
LIST OF REGISTERS
Register Write
Range
Register description
01h
No
02h
No
0 ÷ FFFFFFFF
Main timer value – higher word.
Main timer value – lower word, combined value of registers 01h i
02h defines measured time expressed in seconds.
03h
No
0 ÷ 999
Main timer value - miliseconds
04h
No
0 ÷ 1
Counter state:
0
– counter stopped;
1
– counter is counting
05h
Yes
0 ÷ 4
“StArt”
parameter
(counting start mode)
0 - „Lo-Hi”, 1 - „Hi-Lo”, 2 - „Lo”, 3 - „Hi”
06h
Yes
0 ÷ 1
“StoP”
parameter (counting stop mode)
0 - „Lo-Hi”, 1 - „Hi-Lo”
07h
Yes
0 ÷ 1
“rESEt”
parameter (counter clearing mode)
0 - „Lo”, 1 - „Hi”
08h
Yes
0 ÷ 3
parameter
(main timer displaying format)
0 - „SEc”, 1 - „h-m-S”, 2 - „h-m”, 3 - „h-h10”
09h
Yes
0 ÷ 3
parameter (main timer displaying precision)
0 - „0.000”, 1 - „0.00 ”, 2 - „0.0 ”, 3 - „0. ”
0Ah
Yes
0 ÷ 2
parameter
(displaying format of
totalizer
)
0 - „h-m-S”, 1 - „h-m”, 2 - „h-h10”
0Bh
Yes
0 ÷ 1
“PuSH”
parameter (enabling of control by local keyboard)
0 - „oFF”, 1 - „on”
28
i
