www.haiwell.com
Haiwell PLC - Analog Module Application Case
12 / 18
2.
Module used as remote IO
Haiwell PLC expansion module is built-in one RS485 communication port(Some models with Ethernet communication port), which
not only supports parallel bus(Use the expansion bus to connect with the parallel interface of host PLC), but also supports serial
bus(Use the RS485 communication port of module networking with communication port of host PLC, and host PLC controls the
remote module by communication instructions), when using the serial bus to expand (that is, remote IO module), it doesn't have
expansion limit of system points and can be distributed installation.
Distributed installation is very important for the system which needs to collect and monitor a large number of decentralized digital
or analog signals(temperature, humidity, differential pressure, blowing rate, flow, fan speed, valve opening, etc.), it can easily
achieve distributed installation control and unlimited points of expansion, greatly improving the control system configuration
flexibility and future control expansion capabilities, reducing the number of signal wiring, also reducing the interference problem of
too long analog signal line, saving the project investment costs.
The following will introduce the operation key points and techniques.
2.1. Module power supply
When the module is used as remote IO, there are two optional models of 24VDC and 220VAC, such as S08AI model for the DC
24V power supply. S08AI2 for AC 220V power supply. If the module is powered normally, the PWR indicator will light.
2.2. Communication port introduction
1
All analog modules are built-in RS485 port.
2
As for 8-point analog module, you can choose the Ethernet port.
3
RS485 communication port and Ethernet port can be used at the same time, for example, the RS485 of module
communicates with PLC, Ethernet port can also communicates with multiple host computers (up to 7).
2.3. Communication protocols and default parameters
RS485
: Support standard Modbus RTU / ASCII protocol, it can communicate with the configuration, touch screen, text, PLC
and other third-party host computer, which must support Modbus protocol. Among them:
Address:
1 ~ 254 can be set; module address is divided into soft address and hard address, hard address has the highest
priority.
Soft address
: The address set through programming software - remote tool, address range 1-254;
Hard address
: The address set through the 4-bit DIP switch of module hardware, address range 1-15. Hardware address
setting example:
Baud rate: 2400, 4800, 9600, 19200, 38400, 57600, 115200 optional;
Data format : N, 8, 2 RTU, E, 8, 1 RTU, O, 8, 1 RTU, N, 8, 1 RTU, E, 7, 1 ASCII, O, 7, 1 ASCII, N, 7, 2 ASCII optional.
RS485 default parameter: 19200, N 8 2 RTU, station number is 1.
