HMI and 24 Vdc supply issue

[sayedengg]

Hi all, once again I have got an issue at my factory regarding another type of oven which is fully automated. It has got HMI panel with Allen Bradley micrologix 1500. This oven system has few motors which are run by Allen Bradley Powerflex 700 [ 12 pieces numbers]. Then this system has cutter mechanism which is microcontroller based [ 2 pieces]. The Allen Bradley PLC microlgix 1500 has Digital input and anolog output modules separate. There are few dc and ac relays in this system. Sensors are also included.

This oven is standby type of oven, if the main oven fails or if the production is needed more, then this is brought in. Today, we have tried to start this oven. Its not letting HMI to power up even when the whole oven system is up. SMPS, which is feeding this system the supply of 24 VDC with 6 amps output[ 21 v DC tested @ o/p of SMPS with multimeter]. And we found out the VDC at the i/p of HMI to be 10V dc.

So, what we did, is we gave differet direct 24 Vdc supply to HMI instead of the oven control system . It started up prefectly.

Now, im wondering whether the smps is bad or should we check something else in this oven control system. Please let me what will be the 3way to deal with this type of situation.

Thanks once agin all.

Live and let live

 

[djs]

If the power supply has 21V at its terminals and the HMI has 10V at its terminals, then there is either a bad connection or a partially blown fuse. You will need to trace out the wiring between the power supply and the HMI.

BTW @1V for a 24VDC supply sounds low. You should check if the power supply as a voltage adjustment. lacking that by all means check the loading of the power supply.

 

[sayedengg]

Hi Djs, thanks for the reply. There was a faulty wiring which was causing the problem. The same SMPS was then able to give 21 Vdc at the HMI input which started it up, even though on the HMI it was mentioned 24v DC supply.
I couldnt find any voltage adjustment in the SMPS , only it provided two 24VDC output supply termninals.


Live and let live