User manual - INDICATOR TRS-10a
Register 05h
- operation mode. This register controls operation mode of the module. Value
0000h switches module to "
decimal mode
", and value 0001h – switches it to
"
byte mode
". Other values can not be stored in this register. After writing to
the register 05h, module checks if it's new value is different from previous
value. If new value is different – new operation mode is being initialised ( see
descriptions of registers 01h, 02h i 03h), and symbol "
- - - -
" is showed on the
display. Control of Refresh Time is temporarily off, until first correct write to
any of writeable registers (see description of register 04h). If new value is the
same as previous value then module state will not change, and refresh time
will start counted from 0 (if Refresh period is turned on). Content of register
05h is saved in EEPROM, so after power on it's value is the same as before.
In factoring process, the same address (0xFE) is written to every module. These addresses
can be changed at any time using proper MODBUS commands, or can be forced to be reset
to 0xFF value using module internal momentary switch (to enhance system installation
process, see:
FORCING OF 0xFF ADDRESS
). All settings are stored in non-volatile EEPROM
memory, and available under fixed register numbers.
LED indicator is installed in the module mainboard, it indicates following situations:
•
normal operation mode
- flashes every about 1 second.
•
handmade forcing of address
0xFF
- permanent light
6.
THE MODBUS PRO
TOCOL HANDLING
Transmission parameters:
1 start bit, 8 data bits, 1 stop bit, no parity control
Baud rate:
9600 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 register only) accordingly to Modbus
RTU specification. Maximum group size for 03h function can not exceeds 5 registers (for single
frame).
The device interprets the broadcast messages, but then do not sends the answers.
12
