21
Table 16.3. Response frame format for the READ
function (minimum frame length - 7 bytes):
address of
the device
function 4 or
3
number of bytes in the
data field (max. 70*2=140
bytes)
data field - register value
CRC check sum
1 byte
1 byte
1 byte
2
÷ 140
bytes (HB-LB)
2 bytes (LB-HB)
Example 16.3
. Response frame for register value equal to 0: 0x01 - 0x04 - 0x02 - 0x0000 - 0xB930
Table 16.4. Response frame format for the WRITE
function (frame length - 8 bytes):
copy of the claim frame for the WRITE function (Table 16.2)
Table 16.5. Special answer
(errors:
function field = 0x84 or 0x83 in the case of the READ function and 0x86 in the
case of the WRITE function):
Error code
(HB-LB in the data field)
Error description
0x0001
non-existing register address
0x0002
wrong write register value
0x0003
improper function number
Example 16.5.
Error frame for a non-existing read register address:
0x01 - 0x84 - 0x02 - 0x0001 –0x5130
Table 16.6. Map of registers for the MODBUS-RTU protocol
Register
address
HEX (DEC)
Value
(HEX or DEC)
Description of register and access type
(R- read only register, R/W - read and write register)
0x00 (0)
0
not used or reserved
R
0x01 (1)
653
device type identifier
R
0x02 (2)
100 ÷ 999
controller software (firmware) version
R
0x03 ÷ 0x05
0
not used or reserved
R
0x06 (6)
0 ÷ 7
current status of outputs 1, 2, 3: bits 0, 1, 2, bit=1 means the output is
switched on
R
0x07 (7)
0 ÷ 20,000
current state of the analog output (0 ÷ 20,000 μA or 0 ÷ 10,000 mV)
R
0x08 (8)
-100 ÷ 700
thermocouple cold tip temperature (resolution 0.1
°C
)
R
0x09 ÷ 0x0D
-1,999 ÷ 19,999
measured values (input 1, input 2, difference 1-2, sum 1+2, average)
R
0x0E ÷ 0x10
0
not used or reserved
R
Configuration parameters (chapter 10)
0x11 (17)
0 ÷ 5
parameter 0:
diS1
value indicated for the upper display
R/W
0x12 (18)
0 ÷ 5
parameter 1:
diS2
value indicated for the lower display
R/W
0x13 (19)
20 ÷ 100
parameter 2:
briG
brightness of the display, a 20% increase
R/W
Configuration parameters for the measurement channel numbered
KP
= 0 ÷ 1 (0=channel 1, 1=channel 2)
0x14 (20) +KP*7
0 ÷ 16
parameter 3+KP*7:
inP
type of measurement input (chapter 10)
R/W
0x15 (21) +KP*7
1 ÷ 10
parameter 4+KP*7:
FiL
digital filtration of measurements (response time)
R/W
0x16 (22) +KP*7
0 ÷ 3
parameter 5+KP*7:
dot
position of the point or resolution for temperature
R/W
0x17 (23) +KP*7
-1,999 ÷ 18,000
parameter 6+KP*7:
Lo
lower limit or bottom of the indication range
R/W
0x18 (24) +KP*7
-1,999 ÷ 18,000
parameter 7+KP*7:
Hi
upper limit or top of the indication range
R/W
0x19 (25) +KP*7
-500 ÷ 500
parameter 8+KP*7:
cAo
zero offset for measurements
R/W
0x1A (26) +KP*7
850 ÷ 1,150
parameter 9+KP*7:
cAG
calibration of inclination (sensitivity) for
measurements
R/W
