ICON LevelPro ITC 450 Series Quick Start Manual page 17

LevelPro — ITC 450 & 350 Series
®
Tank Level Display + Controller
RS485 Modbus Programming
11. 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
Baud rate:
Transmission protocol:
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).
i
11.1. LIST OF REGISTERS
Register Write
01h
02h
03h
04h
1
05h
06h
10h
11h
12h
24-0352 © Icon Process Controls Ltd.
are accepted when receive), no parity control
selectable from: 1200 to 115200 bits/second
MODBUS RTU compatible
The device interprets the broadcast messages, but then do not sends the answers.
Range
No -999 ÷ 9999 Measurement value (no decimal point)
The status of the current measurement; 0h - data valid; A0h - top
No 0h, A0h, 60h
border of the measurement range is exceeded; 60h - bottom border
of the measurement range is exceeded;
"Pnt " parameter in "InPt" menu (decimal point position)
Yes 0 ÷ 3
0 - " 0"; 1 - " 0.0"; 2 - " 0.00"; 3 - "0.000"
State of the relays and alarm LED (binary format)
(1 - on, 0 - off): 00000000 000e00ba
Yes see descr. a - relay R1; b - relay R2; e - alarm LED;
If written, only a, b bits are important (others are ignored) these
bits allows user to control the relays via RS-485 interface
State of active current output, expressed in 1/256 mA units – it
Yes 0h ÷ 1800h means that high byte express integer part, and low byte fractional
part of desired output current.
State of passive current output, expressed in 1/256 mA units – it
Yes 2CCh÷1800h means that high byte express integer part, and low byte fractional
part of desired output current.
State of active voltage output, expressed in 1/512 V units – it means
Yes 0h ÷ 1600h that high byte express integer part, and low byte fractional part of
desired output voltage.
No -999 ÷ 9999 Peak (drop) value (no decimal point)
"tyPE" parameter in "InPt" menu (nominal input range).
Yes 0 ÷ 5 0 - 0-20 mA range; 1 - 4-20 mA range; 2 - 0-10 V range;
3 - 2-10 V range; 4 - 0-5 V range; 5 - 1-5 V range
"CHAr" parameter in "InPt" menu (characteristic type)
0 - linear ; 1 - square; 2 - square root; 3 - user defined; 4 - volume
Yes 0 ÷ 5
characteristics of a cylindrical tank in the vertical position; 5 -
volume characteristics of a cylindrical tank in the horizontal position
Yes 0 ÷ 5 "FiLt" parameter in "InPt" menu (measurement filtering rate)
Register description
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