Simex SWI-94, Руководство пользователя

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User manual - WEIGHT METER SWI-94
10. THE MODBUS PRO TOCOL HANDLING
Transmission parameters: 1 start bit, 8 data bits, 1 or 2 stop bit (2 bits are send, 1 and 2 bits
are accepted when receive), no parity control
Baud rate: selectable from: 1200 to 115200 bits/second
Transmission protocol: MODBUS RTU compatible
The device parameters and display value are available via RS-485 interface, as HOLDING-
type registers (numeric values are given in U2 code) 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 16 registers (for single frame).
The device interprets the broadcast messages, but then do not sends the answers.
10.1. LIST OF REGISTERS
Some parameters are located on two registers (higher word in first register, and lower word in
next one). After writing of one of them device controls result of their 32-bit value, and if it is
necessary corrects value of second register automatically. If appropriate modification is
impossible, both registers stay unaffected and device responds with error code 03h
(see:
TRANSMISSION ERRORS DESCRIPTION
).
Register Write Range Register description
01h 1
02h 1
No
-99999 ÷
999999
Measurement value (no decimal point)
03h No
0h
or error no
The status of the current measurement;
0h
- data valid; other
values describe errors (see SIGNALISATION OF ERRORS )
04h No 0 ÷ 2 Decimal point position. The same as 11h register.
05h Yes 0 ÷ 31
State of the relays, LEDs and programmable input (binary format)
(1 - on, 0 - off):
00000000 00fedcba
a - relay R1; b - relay R2; c - LED “NET”; d - LED “ >< ”;
e - LED “ >0< ”; f - programmable input;
If written, only a , b , bits are important (others are ignored) these
bits allows user to control the relays via RS-485 interface
06h 2
Yes 0h ÷ 1800h
State of active current output, expressed in 1/256 mA units – it
means that high byte express integer part, and low byte fractional
part of desired output current.
Yes 2CCh÷1800h
State of passive current output, expressed in 1/256 mA units – it
means that high byte express integer part, and low byte fractional
part of desired output current.
Yes 0h ÷ 1600h
State of active voltage output, expressed in 1/512 V units – it
means that high byte express integer part, and low byte fractional
part of desired output voltage.
07h 1
08h 1
No
-99999 ÷
999999
Peak (drop) value (no decimal point)
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