Dec 9, 2010

Omron HMI NP5 Modbus Communication PLC Programming

Omron HMI NP series are capable to be in connected in MODBUS. Up to 32 HMI can be connected in a network. Through MODBUS you can access the internal registers and coils of HMI and can edit them through PLC programming .

Dip Switch Settings in HMI NP5 for MODBUS :-
If you look at the back side of HMI there are 5 number of DIP switches . Make the following settings .
Dip s/w 1 - ON . Dip s/w 2 - ON. Dip s/w 3 - ON. Dip s/w 4 - OFF.

After making the Dip switch settings you have to make hardware connections , at the back side of HMI there is COM2 and there are 10 terminals . Terminal number 4 is R2- and terminal number 6 is R2+ . Connect the PLCs RS485 port "-" to terminal 4 and "+" to terminal 6 respectively. Note :- In Modbus network always connect "-" with "-" and "+" with "+". Now the hardware connections are over and you have to make some software settings. If you want to review the MODBUS settings for PLC you see here .
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Now open the NP designer software and select the model of the NP and go to settings tab and make the following settings .
Settings of OMRON HMI NP5 for MODBUS:-
PT Unit Number - 1 (This will be the slave ID of HMI in MODBUS network)
Host Unit - 0(this is the master PLC address)
Interface - RS485
Data Bit - 8
Stop Bit - 1
Baud Rate - 9600
Parity - None
Com - Com2

Dont forget to make the similar settings in the PLC. See here.

Now Both the hardware and Software settings are done for HMI to communicate in MODBUS .All we need now is to write the PLC Program .Subscribe to Automation-Talk by Email.
Omron HMI PLC Program:-
As we all know that in MODBUS we have to send the query to the slave devices to read and write the internal registers.
Query / Data format to Write:-

01 (HMI Id) , 0010 (function code), 000B(data bytes) , 0000(data location) , 0003 , 0600 , 0003 , E800

Here we have shown the data location as 0 but real location is 1 (we have to subtract 1 from the real data location in MODBUS Query). The data that will be written in data location 1will be 03e8 which is equivalent to 1000 in decimal.

Query / Data format to Write:-

01 , 0003 , 0004 , 0000 , 0003 (data location)

While reading we always add 1 in data location . So in the above we have written 3 but actually we are reading the data location 2.

This POst will definately help you to understand the MODBUS communication of HMI . Keep reading here for the full PLC program of Omron HMI . Dont forget to Subscribe to receive all the updates in urs E-Mail.
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  1. Dear sir!
    could you teach me how connect np series to s7 200 cpu 224xp
    I made following the "host connection manual" document but not success.

    with case rs 232
    plc(ppi cable) np
    with case rs485
    sw2 1:on, 2,3,4 off
    plc np

  2. The Connection you have made is for Programming Cable of Omron.
    What type of Port is in S7 200 . is it Male DB 9 or Female DB9

  3. For RS485 connection you just have RS485 port in PLC if Siemens PLC support then connect NP RS485 (+ve) with PLC + and Negative with negative.

  4. If i were you i have connected
    NP PLC
    4-- 4--
    SC SC
    5-- 5--

    where SC is short circuit
    Hope it helps you.

  5. well as correctly said by FYP ..just short the terminals 4 and 5 on both the sides i.e plc and np.2------------3
    iam sure with this will work and they will communicate.......


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