Siemens 353 User Manual

UM353-1B Network Communications
April 2012
5-1
5.0 NETWORK COMMUNICATIONS
This section provides an overview of the data that can be obtained from the 353 using Modbus, or Modbus/TCP
Ethernet, which provides Modbus over Ethernet protocol. In the Modbus/TCP protocol all listed Modbus items are
available and are embedded in the Modbus/Ethernet protocol frame. Refer to Section 6 Data Mapping for detailed
list of the actual data. Go to the Modbus-IDA Website
http://www.modbus.org/ for more information on Modbus
and access to Modbus technical specifications.
5.1 MODBUS DATA MAPPING
Modbus is a master/slave protocol where a master device (e.g. PC-based operator workstation) sends commands to
one slave (i.e. Siemens 353 Process Automation Controller) and waits for a response. When using RS485 network
communication, each station has a unique network address (1-32), configured as part of the station parameters.
When using Modbus/TCP protocol each station has a unique IP address. Ethernet enables all 353 controllers on the
Ethernet network to be masters, thus providing peer-to-peer network relationships between controllers.
Data is assigned to either a register (16-bit word) or a coil (1-bit). An IEEE floating point number (Real) is
assigned to 2 consecutive registers with the first containing the most significant and the second the least significant
portion of the floating point number. The 353 uses an IEEE reverse format. See Table 3-4 in Section 3.2.7 AIE_-
Analog Input – Ethernet for more information on floating point formats.
The station supports Modbus function codes 01, 02, 03, 04, 05, 06, 08, and 16. Section 6 Data Mapping provides a
listing of available data and specific locations within the Modbus map. The following is the overview for the
complete 353 series controllers Modbus data mapping.
Station Coils......................................................................................x0001 - x0071
Loop Coils.........................................................................................x0296 - x1495
Extended Loop Coils (ODD Pushbuttons)........................................x8701 - x9100
Sequencer Loop I/O Coils (ref. MSLCP pointer) ............................x1496 - x2263
LonWorks Remote I/O Coils (352P, 353”A”, & 354/354N) ............x2401 - x3976*
Ubus Discrete I/O States & Forcing (353R) .....................................x4001 - x5500
(spares)..............................................................................................x5501 - x9100
Loop PCOM Block Coils..................................................................x9101 - x9999
Station Data (16-bit integer)..............................................................x0001 - x0100
Station String Data (ASCII)..............................................................x0101 - x0200
Loop Dynamic Data (16-bit integer).................................................x0201 - x0450
Loop Variable Data (16-bit integer)..................................................x0451 - x1200
Loop Static Data (16-bit integer) ......................................................x1201 - x1950
Loop Dynamic Data (32-bit floating point) ......................................x1951 - x2450
Loop Variable Data (32-bit floating point) .......................................x2451 - x3950
Loop Static Data (32-bit floating point)............................................x3951 - x5450
Loop String Data (ASCII).................................................................x5451 - x7950
Ubus Module Types (353R)..............................................................x7951 - x8000*
Loop Trend Data (ref. MLTP pointer) ..............................................x8001 - x9000
(spares)..............................................................................................x9001 - x9999
* Areas of the map that apply to other 353 products and do not apply to the 353 Design Level B.

Siemens 353 Specifications

General

Brand	Siemens
Model	353
Category	Controller
Language	English