ICP DAS USA MDC-700 Series User Manual page 19

Polling Definition
The Polling Definition is used to define Modbus commands to read data from the slave devices.
Before attempting to configure the parameters for the Polling Definition, be sure to check the Com
port number that the target device is connected to, the Modbus ID setting for the target device, and
the function code, start address, and the quantity for reading data.
# UseComPort SlaveModbusID FunctionCode RegStartAddr RegCount
* 1
* 1
* 2
* 3
* 4
* 5
Each Polling Definition consists of 6 parameters listed as below:
# Defines the type for a polling definition. In the MDC‐700, it provides three types:
"*": Asterisk symbol means that this is a valid polling definition. The MDC‐700 will
"‐": Minus sign means that this is a disabled polling definition. The MDC‐700 will
"": Empty means that this is a null polling definition. The MDC‐700 will neither
UseComPort Defines the COM port number to which the slave device is connected. The COM
port number can be 1 or 2 for MDC‐711, and can be 1, 2, 3, 4 or 5 for MDC‐714
and MDC‐741.
SlaveModbusID Defines the identification of the remote slave. The valid range is from 1 to 255.
FunctionCode Defines the request function code. A valid code can be 1 (Read DO), 2 (Read DI), 3
(Read AO) or 4 (Read AI) depending on the I/O features of the slave device.
RegStartAddr Defines the starting address, i.e. the address of the first register specified.
The available range is from 0 to 9599.
RegCount Defines the quantity of registers to be read. The available range is from 1 to 64.
NOTE:
The maximum number of all the polling definitions is 240.
The MDC module provides 9600 internal Modbus registers each table (DI/DO/AI/AO) to hold
data collected from the RTU slave devices.
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1
1
2
3
4
5
assign local register for data defined in the definition and save the polled data
to the mapping local register.
assign local register for data defined in the definition but will not poll data.
assign local register for data defined in the definition nor poll data.
1 0
2 0
1 0
2 0
3 0
4 0
8
8
4
4
4
4