Siemens SEZ50MB Operating Instructions page 2

Before turning on the power supply of SEZ50MB, please do the followings:
l
Check all required connections on the RWD device;
l
Configure RWD device to a desired application manually or via RWD SW tool and check if the
standalone operation of this RWD is working properly (refer to RWD datasheet for more details);
l
Set the 8-way DIP switch for SEZ50MB device address. If more than one SEZ50MBs are used within
the same Modbus network, different device addresses should be used for every SEZ50MB;
l
Set the 4-way DIP switch for SEZ50MB communication settings, and the same communication
settings should be applied to all SEZ50MBs connected to the same network;
l
Connect the RS232 cable between RWD device and SEZ50MB;
l
Connect PC RS232 port with a RS232-TO-RS485 converter or connect USB port with a USB-TO-
RS485 converter (converter with electrical isolation is highly preferred);
l Connect the RS485 side of the converter with the Modbus interface (+, -, Ref) of SEZ50MB – If
multiple SEZ50MBs are used on the same Modbus network, it is recommended to use a single BUS
type topology and to terminate the Modbus network with a termination resistor of 150 Ω for the best
performance.
SEZ50MB Modbus Specifications
The Device Addresses for SEZ50MBs are from 1 to 247 while the valid Function Codes are as follows:
Function Data
Functions
Code (Hex) Length
0x01 1 Read R/W Flag (Coil)
0x05 1 Write R/W Flag (Coil)
0x02 1 Read R-only Flag (Discrete Input)
0x03 2 Read R/W Register (Holding Register)
0x10 2 Write R/W Register
0x04 2 Read R-only Register (Input Register)
Examples of using different function codes
Using Function Code 0x01 to read RWD32S parameter (ADDR = 00001) called "bFrostEnable" with
Modbus ADDR = 0000:
SEZ50MB Function
Device Address Code
Send F7 01
SEZ50MB Function
Device Address Code
Respond F7 01
Using Function Code 0x02 to read RWD68 parameter (ADDR = 10005) called "Q1_output" with Modbus
ADDR = 0004:
SEZ50MB Function
Device Address Code
Send F7 02
SEZ50MB Function
Device Address Code
Respond F7 02
Siemens Building Technologies / HVAC products
RWD Parameter Addressable
Ranges
0xxxx
e.g. 00001, 00003
1xxxx
e.g. 10004
4xxxx
e.g. 40109, 40111
3xxxx
e.g. 30001, 30007
Modbus Address Data Length CRC16 Check
00 00 00 01 E9
Byte Status CRC16 Check
Count
01 01 A3
(bFrostEnable = Enable)
Modbus Address Data Length CRC16 Check
00 04 00 01 EC
Byte Status CRC16 Check
Count
01 00 92
(Q1_output = Off)
B3099
Using Function Code 0x03 to read RWD68 parameter (ADDR = 40117, 40118) called "SP3day" with
Modbus ADDR = 0116, 0117:
SEZ50MB
Device Address
Send F7
SEZ50MB
Device Address
Respond F7
Using Function Code 0x04 to read RWD68 parameter (ADDR = 30055, 30056) called "RWDAPP" with
Modbus ADDR = 0054, 0055:
SEZ50MB
Device Address
Send F7
SEZ50MB
Device Address
Respond F7
Using Function Code 0x05 to write RWD32S parameter (ADDR = 00001) called "bFrostEnable" with
Modbus ADDR = 0000:
SEZ50MB
Device Address
Send F7
SEZ50MB
Device Address
Respond F7
Note: Only two possibilities for Value above - writing a "0" using Value = 00 00
Using Function Code 0x10 to write RWD68 parameter (ADDR = 40117, 40118) called "SP3day" with
5C
Modbus ADDR = 0116, 0117:
SEZ50MB
Device Address
Send F7
C0
SEZ50MB
9D
Device Address
Respond F7
Note: This operating instruction provides information about the setup and the overall Modbus requirements.
For RWD parameters, IO signal status and their corresponding Modbus addresses, please refer to
00
the SEZ50MB User Manual CB1P3099en for more information.
20.10.2009
Function Modbus Address Data Length
Code
03 00 74 00
Function Code Byte Count Status
(IEEE 754 format)
03 04 41 E0 00 00
(SP3 day setpoint 28 °C)
Function Code Modbus Address Data Length
04 00 36 00
Function Code Byte Count Status
(IEEE 754 format)
04 04 42 48 00 00
(Application No. is 50)
Function Code Modbus Address Value
05 00 00 FF
Function Code Modbus Address Value
05 00 00 FF
or writing a "1" using Value = FF 00.
Function Code Modbus Address Data Length
10 00 74 00
Data Byte Status
Length Count (IEEE 754 format)
From 04 41 E8 00 00
(SP3 day setpoint 29 °C)
Above
Function Code Modbus Address Data Length
10 00 74 00
© 2009 Siemens Switzerland Ltd.
Subject to change
CRC16 Check
02 90 87
CRC16 Check
79 F6
CRC16 Check
02 85 53
CRC16 Check
92 00
CRC16 Check
00 98 AC
CRC16 Check
00 98 AC
Byte
Count
02 To below
CRC16
Check
7C FB
CRC16 Check
02 15 44
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