MODULE URA-0800O

[ORDETEC]

Hello, I am using the URA-0800O module and my question is as follows:
- Is it possible to connect several 4-wire sensors to this module, that is, where each sensor is an active type? - Personally I think that it cannot be because all the inputs share the same common-
- If it cannot be done, which remote type module could I use?

Thank you.

[Simon]

Hi,

It all depends on the reasons why you need to use a 4-wire sensor.  Often a 4-wire sensor is used so that it can have a signal common that is galvanically isolated from the power supply common.  Is that a requirement for you?  Note also that the URA0800O does not have galvanic isolation between the input commons and the 0V supply common.

If you don't need isolation, you can use the above module, as follows:

* link all the sensor +24V supply terminals to the main +24V supply

* Link all the sensors 0V supply terminals to the main supply 0V

* Unless the sensor user manual specifically says not to, link all the sensor signal grounds to 0V common.  If possible do this at the sensor rather than at the PLC, to avoid earth loops.

* connect the sensor signal outputs to the input channels of the URA-0800O

Note also that the URA0400O has 4 inputs and 4 commons, which gives you a convenient terminating point for the signal ground wire. 

If you know that you need isolation, or if the sensors are on very long cable runs and/or a noisy electrical environment, then i would suggest using signal isolators in the same cabinet as the URA0800O units.

 

Hope this helps.

[ORDETEC]

Thank you very much for your help Simon.