Siemens AO strange or stupid problem

[spaderkung]

Hi all!

On my system with a S7-319 and a couple of IM151 nodes I do not get the AO cards to work.

The fault appears on all nodes... DI, DO, and even AI after the same PM as the AO is on are working fine. Tried "forcing" QW to rule out program error.

AO configured 4-20 mA. Also tried 0- 20. Always 0 mA measured between 1 and 3 (5 and 7). (And the actuator does not move either). No other connections to card. Tried other AO cards of same type.

No profibus errors.

AO card: 6ES7 135-4GB01-0AB0.

Grateful for any comments.

 

[L D[AR2P#0.0]]

What value are you writing to the AO ?

See table below:

 

[KalleOlsen]

Try to use the ET200S configurator and put in your terminal modules and cards. There is a button for a potential overview there somewhere. Could be an evil terminal block that breaks the 24V supply.

Kalle

 

[spaderkung]

Thanks.

Found some diagnostic setting and found that there was an "wire break". After reviewing the electrical drawing the error was corrected - a combination of broken fuse in the ampere meter and switched actuator connections...

 

[KalleOlsen]

broken fuse in the ampere meter

The ultimate classic error

 

[JesperMP]

a combination of broken fuse in the ampere meter

That was my first thought.
Somehow the mA fuse is always blown when I get my meter back after having loaned it to someone.

A tip: Always have a 250-ohm resistor at the ready in the toolbox. You can quickly hook the resistor up over the output terminals, and then see if you can measure 1-5 volts over the resistor.