Created Date: January 18,2010

Created by: KPrice

sttchui, yes, you do need to address your power problem first. This could be causing your problems, damaging components, or be a shock hazard.

Your neutral must be grounded/bonded so your L-N voltage and L-G voltage are equal, and your N-G voltage is zero. This is for your utility service and your step-down transformer, if used. This is for your single-phase 240V/120V, or 208V/120V "Y " 3-phase, or older 240V delta with 1-midpoint as neutral. It sounds like you may have this older delta system. (you may see a slight N-G voltage on a heavy-loaded feeder system)

Check the neutral-ground bonding (main bonding jumper), and your ground rod and building steel connections. Check these connections at service entrance and transformers. Call the utility to have them check their line transformer grounding. There are electrical contractors that specialize in building services and grounding. They would have testers to test resistance to ground.

I'm in the US. Other countries, although different voltages, would have similar grounding (earthing) requirements.

I hope you get this fixed.

Created Date: January 17,2010

Created by: sttchui

Hi,

I have DL305 series PLC using DL340 CPU & analogue input card F3-04ADS, which have been running for few years without any major problem, until recently

Problem

1) The CPU run indicator will run normaly before any operation start, but when we try to run the operation after few step, the CPU run indicator will turn off, then the CPU indicator will turn. Everything come to halt. As i look through the manual it more related to hardware problem, as far as i know we didnt change or add anything new hardware to the PLC. i have replace with new CPU , base & IO yet sometimes this problem still occur!

Now the CPU running stable, sometimes the analogue input card goes hairwire.

2) The Analogue input F3-04ADS(0-10VDC setting) which i have to 2 card inside my base(slot 1 & slot 6). i found the 2nd card(slot no 6) the input always show 4095 which are the maximum analogue value without any voltage(OVDC) or when the wiring attach to it is remove. We have to replaced the card & everything work for a day,now my card again showing same error which i have to replace with another card, & it run back normal again. i have check power supply 10VDC is giving a correct DC supply

i check the supply AC voltage to the CPU base is 110VDC(L& N) but when i compare it to L & E i getting 250-300VAC which abit strange. So i replace the supply power only for CPU with different supply 110VAC & when i compare the ground is getting around 79VAC

Could it be noise problem or floating current causing this problem??? anyone have any solution or idea to solve this problem?or could it be the power budget excedded?? or there is short circuit in the analogue input module?

D3-10B-1 - 1

CPU340 - 1

F3-04ADS - 1

F3-04DAS - 1

D3-16NE3 2

D3-16TR - 1

F3-04ADS - 1

D3-16TR - 1

D3-08TRS-1 - 1

thank you

Regards

sttchui