Product Overview
Table Of Contents
© Danfoss | DCS | 2019.04
Data sheet | Superheat controller type EKE 1A, EKE 1B, EKE 1C
DKRCC.PD.RS0.A4.02 | 26
8.3 RS485 bus function
codes overview
Function code Function name Function description
(0x03)
Read holding registers This function code is used to read the contents of the continuous block of
holding registers in a remote device.
(0x06)
Write single register This function code is used to write a single holding register in a remote
device.
(0x10)
Write multible registers This function code is used to write a block of contiguous registers
(1 to 123 registers) in a remote device.
(0x2B) Read device identication Support of mandatory information.
8.4 Example:
MODBus
communication
Note:
In bus communication,
only MET (SI) system
can be used.
Metric unit (MET):
temperature, temperature
oset and pressure units
in MMIGRS2 display °C , K
and Bar Gauge respectively
Note:
setpoint needs to be scale
by X10 . i.e 5 deg C =50
(HEX: 32)
The following example illustrate the way of reading and writing the PNU numbers shown below
PNU Parameter name
3006 R101 Temperature setpoint
3007 R001 Dierential
PNU Parameter name
3006 R101 Temperature setpoint
3007 R001 Dierential
Function 03 read register
Example 1: Read 2 register from 3005 i.e 3005-3006, i.e PNU 3006-3007, from device address 1 (in blue)
TX: [01][03][0B][BD][00][02][56][0B]
RX: [01][03][04][00][1E][00][14][9A][3A]
Result
Read temperature setpoint and dierential
PNU Parameter name Value
3006 R101 Temperature setpoint 30 (3.0)
3007 R001 Dierential 20 ( 2.0)
Function 06 write register
Example 2: Write R101 Temperature set point to 5.0 (50 0x32)
TX: [01][06][0B][BD][00][32][9A][1F]
RX [01][06][0B][BD][00][32][9A][1F]
Slave acknowledge
Function 0x10 write multiple register
Example 3: Write R101 Temperature set point to 4.8 (48 0x30) and R001 Dierential to 10.0 (100 0x64)
TX: [01][10][0B][BE][00][02][04][00][64][00][30][4B][AC]
RX: [01][10][0B][BE][00][02][23][C8]
Slave acknowledge