Results:
Both steps 3a and 3b will result in outputs being activated as below. The only difference being that step 3a will set
and clear all 16 bits where as step 3b will only set the specified bits and will have no affect on the others.
Bit Number Status Bit Number Status
0 0 8 1
1 1 9 0
2 0 10 1
3 1 11 0
4 0 12 1
5 1 13 0
6 0 14 1
7 1 15 0
Example #2
DMC-4143 connected as a Modbus master to a 3rd party PLC. The DMC-4143 will read the value of analog inputs 3
and 4 on the PLC located at addresses 40006 and 40008 respectively. The PLC stores values as 32-bit floating point
numbers which is common.
1. Begin by opening a connection to the PLC which has an IP address of 192.168.1.10 in our example
IHB=192,168,1,10<502>2
2. Dimension an array to store the results
DM myanalog[4]
3. Send the appropriate MB command. Use function code 4 (as specified per the PLC). Start at address
40006. Retrieve 4 modbus registers (2 modbus registers per 1 analog input, as specified by the PLC)
MBB=,4,40006,4,myanalog[]
Results:
Array elements 0 and 1 will make up the 32 bit floating point value for analog input 3 on the PLC and array
elements 2 and 3 will combine for the value of analog input 4.
myanalog[0]=16412=0x401C
myanalog[1]=52429=0xCCCD
myanalog[2]=49347=0xC0C3
myanalog[3]=13107=0x3333
Analog input 3 = 0x401CCCCD = 2.45V
Analog input 4 = 0xC0C33333 = -6.1V
Example #3
DMC-4143 connected as a Modbus master to a hydraulic pump. The DMC-4143 will set the pump pressure by
writing to an analog output on the pump located at Modbus address 30000 and consisting of 2 Modbus registers
forming a 32 bit floating point value.
1. Begin by opening a connection to the pump which has an IP address of 192.168.1.100 in our example
IHB=192,168,1,100<502>2
2. Dimension and fill an array with values that will be written to the PLC
DM pump[2]
Chapter 4 Software Tools and Communication ▫ 45 DMC-41x3 User Manual
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