ADDR
FUNC
01
03
REG H,L
00
01
COUNT H,L
00
01
CRC L,H
D5
CA
these registers are active only if device is equipped with current or voltage output
after writing to register no 20h the device responds with an “old” address in the message.
after writing to register no 22h the device responds with the new baud rate.
the value of the “mbAc” parameter is also connected to write to this register, so it is possible to block a
writes, but
impossible to unblock writes via RS-485 interface, The unblocking of the writes is possible from menu
level only.
The pairs of
„X -Y”
coordinates may be defined for any free point. The pair is “free” (it means that
particular point is
not defined) if
„X”
coordinate of this point is equal 8000h. After writing both X and Y coordinate the
point is defined
and used in calculation of result. The coordinates of any point can be changed at any time.
If an error occurs while write or read of single register, then the device sends an error code according to
Modbus RTU specifications (example message no 1).
Examples apply for device with address 1. All values are represent hexadecimal.
1. Read of the displayed value (measurement), ITC 450 device address = 01h:
Field description:
ADDR
Device address on modbus network
FUNC
Function code
REG H,L
Starting address (address of first register to read/write, Hi and Lo byte)
COUNT H,L
No. of registers to read/write (Hi and Lo byte)
BYTE C
Data byte count in answer frame
DATA H,L
Data byte (Hi and Lo byte)
CRC L,H
CRC error check (Hi and Lo byte)
Error codes :
01h
- illegal function (only functions 03h, 06h and 10h are available),
02h
- illegal register address
03h
- illegal data value
08h
- no write permission (see:
“mbAc”
parameter)
A0h
- exceed of upper border of input range
60h
- exceed of lower border of input range
A0h
and 60h codes can appear only during reg. 01h is reading by 03h function (read of a single register).
11.2. TRANSMISSION ERRORS DESCRIPTION
11.3. EXAMPLES OF QUERY/ANSWER FRAMES
1.
2.
3.
4.
5.
50
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ITC 450/470
User manual
Summary of Contents for ITC 450
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