S7-1500 analog inputs not reading

[A_G]

I'm pretty new to Siemens. I just downloaded a new program into a new S7-1500 CPU. All modules are ok/not faulted. here is the problem: i have 4 analog input cards. The 4th one's inputs are reading normally. The remaining 3 cards all have their inputs reading 0 or negative. All wiring appears to be correct. Thanks in advance for any help!

 

[Ken Moore]

Thinking out loud.
Are they are voltage/current cards? Are they setup correctly?
If you swap the cards, does the problem follow the card?

 

[A_G]

Thanks for your reply. The cards are all set up for 4-20 mA in all channels. All the devices are supposed to be 4-20 mA. There are three cards that are having this problem. One card is reading normally. I guess I could swap one of the "problem" cards with the one "good" card. It just seems odd that there are three cards with this problem.

 

[slp530]

Are all your 4-20ma analog inputs the same i.e 2-wire/ 4-wire or a mixture of the two

 

[bkottaras]

Thanks for your reply. The cards are all set up for 4-20 mA in all channels. All the devices are supposed to be 4-20 mA. There are three cards that are having this problem. One card is reading normally. I guess I could swap one of the "problem" cards with the one "good" card. It just seems odd that there are three cards with this problem.

Have you wired all the cards correctly?
Analog ones need supply voltage besides the actual channel wiring.
Possibly the first in the rack is wired and the following 3 are not. The supply power is external, meaning, nothing goes through the backplane.
Also bridges can be used with the front connectors. Are you missing those?
Look for an Man terminal or something like that, going by memory here, see if wires are landed to all of them or bridges,

 

[bkottaras]

Wiring

Here's a page from the 1500 manual for analog modules.

 

[A_G]

It looks like the only card that is reading ok is the card with 4 wire devices. The "bad" cards all have only 2 wire devices. But I'm not sure what this means. Also the "good" card is the last in the rack.

 

[A_G]

Update: fixed it by changing from 4 wire to 2 wire in settings in card device properties in TIA Portal. Thanks everyone!