AI880 fluctuation reading at channel 1

I had installed 6 redundant units of AI880 with TU844 and TY801 in once cluster.

During connecting the field device to channel 1 on Slot 1 - 3, I observe that there is fluctuating reading occur at the channel 1 reading about 0.016% variance.Other channels in the module are not affected. The remaining slot also not affected

I inspect the module and found no incorrect wiring for both power and fied connection.

To find the cause, I had:

i. Inspect the module and found no incorrect wiring for both power and fied connection.

ii. Remove the field connection and monitor the channel value. But the value is still fluctuate

iii. Change the baseplate and IO module to new tested unit but the signal is still fluctuate on the slot 1 -3. The remaining slot is no

iv. Measure the loop voltage from IO channel and the result is +22.4 VDC.

v. Change the loop to 2nd channel and no fluctuation occurs.

vi. Verify the shunt stick and the installation is correct.

vii. Inspect the module and found no incorrect wiring for both power and fied connection.

viii. Grounding for system cabinet is still pending as it is in commisioning phase

As per above findings, I'm unable to find the cause of error.

Attached are the snapshot of the AI880

In the picture the Channel 1 before fluctuating occur (reading = 0) and the following picture is during fluctuating occur (reading = 2.1 kPag). The range of this channel is 0-13000 kPag.

The following pictures are the setting for the AI880 module.

 Channel 1 No fluctua.jpg

 Channel 1 Fluctuatio.jpg

 AI880 setting 1.jpg

 AI880 setting 2.jpg

Add New Comment


asked 7 months ago



With a 12 bit A/D converter, the **BEST** accuracy you can get is about 0.025 % of full scale range. And thats before you worry about any other normal sources of error.

2.1 Kpa in a 0..13000 kPa range is nothing.

Rob Lyon   

answered 7 months ago


By Teleng on 8/4/2017 | Like (0) | Report

Does this is due to conversion error? When I check the loop power = 24VDC and loop current during normal is 4 mA.

Add New Comment

Get weekly AKS updates

Partner Exclusive Webinars


> – Login to the partner portal to register

Points Redemption Program - Redeem your points for ABB training, Bluetooth speakers and mugs. Terms and conditions >

Earn points when you refer a friend
AKS Referral Program is "Live" - Learn more

AKS Experts

Ask Ronny Lindström   

Rank: 17

ABB Service Engineer

Ask Govindaraj   

Rank: 10

Working in ABB India Operation Center. Have Project engineering and commissioning experience in ABB 800xA, Freelance, AC500.

Ask Flavio Mussolin   

Rank: 4

ABB AVP, Senior Electronic and Automation Engineer with over 30 years of experience in the field of process automation automotive, pharmaceutical, hollow glass, steel and rolling.

Ask nikismith   

Rank: 247

I have been a part of the Recording & Control Factory team for 17 years in total, having spent a number of years as a repairs technician withi the manufacturing department, but being in my current role for 9 years now.

Ask MMM   

Rank: 5

ABB PA CT Technical Support

Ask Dieter Henkel   

Rank: 19

Ask Rob Lyon   

Rank: 2 I'm an independent DCS software and commissioning engineer with extensive experience in 800xA and other ABB products. I've worked in almost every corner of the world and still haven't seen it all.

Ask Harsha.D   

Rank: 7

Tech.Support,software and commisioning engineer with Proficient knowledge in 800xA and its products, RNRP,Networking in general.

Ask WvanWees   

Rank: 6

I'm a senior service engineer working for ABB in The Netherlands.

Ask kstoilov   

Rank: 11

Control System Engineer: 800xA, Compact 800, AC500, AC31-50, Advant Master, Simatic, AC&DC Drives 11 years worked for ABB - Control Systems

Ask Stefan Stromqvist   

Rank: 1

I joined ABB in the year of 1994 and has since 1999 been working as a Service & Support Engineer at BU Control Technologies in Västerås, Sweden. My areas of expertise are: 800xA Base, 800xA for Advant Master, Information Management, operating systems, RNRP and Ethernet comms/networking in general.

Ask Sumit Gargav   

Rank: 3

I have worked with Freelance in majority, with 800xA FD and Melody system partly. Also had opportunity to work with Protocols - HART,Profibus,FF & Modbus.