F2-8AD4DA-1 failures Analog Module Cold Start Failures

[AdchemElectrician]

Hi everyone,

I'm hoping someone has come across this issue before.

I'm running several DL205 H2-DM1E systems with F2-8AD4DA-1 analog input/output modules.

The problem is that after the PLC has been powered down, the analog module often fails to initialise correctly when power is restored. When this happens:

All analog input raw values remain at 0.
The PLC starts normally.
The module is still detected and appears to be present.
The fault affects all analog inputs simultaneously.

The interesting part is:

If I gently warm the analog card with a heat gun for a short time, it starts working normally.
Once it has started, it continues to operate correctly until the next power cycle.
We've also found that changing the startup sequence or occasionally reseating the module can sometimes get it going, but the next cold start usually causes the problem again.

This isn't an isolated case. Over the past 12 months we've had around 10 F2-8AD4DA-1 modules develop the same fault, and we have approximately 60 modules installed across our site. It's becoming a significant reliability issue, so if there is a known repair or common component failure, we'd much rather repair the modules than replace them.

At this stage I'm suspecting an ageing component on the module, such as an electrolytic capacitor, voltage regulator, or another startup-related component, but I haven't started replacing parts yet.

Has anyone experienced this with the F2-8AD4DA-1?

I'm particularly interested in:

Whether this is a known failure mode.
Which components are most commonly responsible.
Whether anyone has successfully repaired one (for example by replacing capacitors).
Whether Host Engineering has identified a common cause.
Any recommended checks or measurements before I start replacing components.

Any advice would be greatly appreciated.

Thanks,

Matt

[BobO]

Hi everyone,

I'm hoping someone has come across this issue before.

I'm running several DL205 H2-DM1E systems with F2-8AD4DA-1 analog input/output modules.

The problem is that after the PLC has been powered down, the analog module often fails to initialise correctly when power is restored. When this happens:

All analog input raw values remain at 0.
The PLC starts normally.
The module is still detected and appears to be present.
The fault affects all analog inputs simultaneously.

The interesting part is:

If I gently warm the analog card with a heat gun for a short time, it starts working normally.
Once it has started, it continues to operate correctly until the next power cycle.
We've also found that changing the startup sequence or occasionally reseating the module can sometimes get it going, but the next cold start usually causes the problem again.

This isn't an isolated case. Over the past 12 months we've had around 10 F2-8AD4DA-1 modules develop the same fault, and we have approximately 60 modules installed across our site. It's becoming a significant reliability issue, so if there is a known repair or common component failure, we'd much rather repair the modules than replace them.

At this stage I'm suspecting an ageing component on the module, such as an electrolytic capacitor, voltage regulator, or another startup-related component, but I haven't started replacing parts yet.

Has anyone experienced this with the F2-8AD4DA-1?

I'm particularly interested in:

Whether this is a known failure mode.
Which components are most commonly responsible.
Whether anyone has successfully repaired one (for example by replacing capacitors).
Whether Host Engineering has identified a common cause.
Any recommended checks or measurements before I start replacing components.

Any advice would be greatly appreciated.

Thanks,

Matt

That's not a Host product, FACTS Engineering makes it.

[AdchemElectrician]

Thank you for your reply I will speak to them.