PLC-HMI power issue

[usmanqadir91]

Hi

I am using Delta DVP-20-SX2 PLC and Weintek MT8071IP HMI.

I am experiencing a very strange issue. Whenever, i connect PLC and HMI to the same power source the PLC seems to freeze and does not perform required operations.

However, when i connect PLC and HMI to separate power sources, the PLC keeps on performing its normal operation and updates data on HMI regularly.

I have searched various forums and could not come up with an answer to why connection with same power source freezes PLC.

Any help will be highly appreciated as it is not feasible to connect separate power sources for PLC and HMI.

[andreyit]

What is the output current of the power supply?

[usmanqadir91]

I have tested PLC and HMI with two different sources one has output current of 1 Amps and other one has output current of around 5 Amps.

[andreyit]

power consumption DVP-20-SX2 - 600mA
power consumption MT8071IP - 350mA
+50% = ~1,5A power supply should be.
you test hmi+plc on 5A power supply?

[usmanqadir91]

Thank for the reply.

Yes i tested it with 12 V 7.3 Ah battery connected through Adjustable Boost /Step up Converter Module 150W, 10-32V to 12-35V (dc to dc). However, the results was the same and PLC, HMI freezes when connected simultaneously with the same battery.

[andreyit]

hmm. Are you all grounded? The PLC does not have enough power or something interferes with it.

[usmanqadir91]

The grounds are all common, however, i am unable to figure out what is interfering with PLC.

One other thing i noticed is that if HMI is connected and then i wire in PLC with the power source, the HMI restarts itself because the fuse of power switches off for a split of a second.