Samba Analog input: Sourcing or Sinking

[Jeff164]

Maybe this is a dumb question...but I'd rather ask than make an even dumber erorr.

I'm familliar with discrete inputs, and that they can be sourcing or sinking. 

Typically I use a Sourcing input and the modulating analog signal (postive voltage, current flow going into the PLC input)  is then dropped across an internal load in the PLC and is shunted to the 0 volt reference on an internal buss of the PLC.

I've never heard the term applied to an analog input before -  but to me, they would also be sourcing inputs, and function in a similar manner.  I have a new transmitter to work with and its a 3 wire 4-20 signal.  Tech literature with the transmitter shows that it is selectable to be configured for a sourcing or a sinking analog input.   I dont see anything in the installation guide of the PLC other than the jumper 12 for selecting sourcing / sinking discrete inputs and the other jumpers for configuring the analog inputs. 

The diagram in the install guide to me looks like the analog input would be termed as "Sourcing" and that the load resistor is internal to the PLC.   I've wired these sucessfully before - Just never came across anything describing an alalog input with these terms.   

PLC in question is a SM70-J-TA22  

thanks 

  

[kratmel]

2 hours ago, Jeff164 said:

Tech literature with the transmitter shows that it is selectable to be configured for a sourcing or a sinking analog input.

Please post transmitter model numbers or manual in pdf format.

[Jeff164]

Transmitter is a Honeywell XCD.  below is a screen grab from the manual, but I've included a link as well.   Based on this,  I'm anticipating using their "Source" diagram and what I'm planning at this point

• 24 volt power to pin 1 of transmitter from instrument power supply.
• 0 vdc to pin 2 of transmitter and pin 2 (0V) of Samba input terminals 
• 4-20 mA signal from pin 3 of transmitter to pin 10 / I5 of Samba
• All Samba jumpers will be set to B except 11.  

I have a dialog open with transmitter tech rep as well, wasnt sure which way to approach this.  

Honeywell XCD Tech Manual

[kratmel]

14 hours ago, Jeff164 said:

• 24 volt power to pin 1 of transmitter from instrument power supply.
• 0 vdc to pin 2 of transmitter and pin 2 (0V) of Samba input terminals 
• 4-20 mA signal from pin 3 of transmitter to pin 10 / I5 of Samba

And JP4, JP10 set to B - enough to get the right analog signal in "Source" transmitter mode. Please Note I5 >>>>> AN3 analog input. 

 

14 hours ago, Jeff164 said:

All Samba jumpers will be set to B except 11. 

I think you want to setup 3 channel temperature mesurement via Samba. In your configuration present Two PT100 sensor and you need to use transmitter for set channel #3 PT 100 to 4..20mA and connect it to AN3 analog input.

If it is true - you must set J11 to B also.  

Then you can connect both #1 and #2 PT100 sensor Common wire to CM PT100 (I11 Samba pin). 

[Jeff164]

Thanks for reply.   Inputs 7/8  & 9/10  will be set to Thermocouple input.   Input 5 & Input 6 will both be analog 4-20 inputs 3 & 2 respectivly.   

I got confirmation from the vendor of my 3 wire transmitter about their equipment as well, so my impressions about the Sourcing input were correct.  It through me  a curve initially, wasnt expecting to see the "option" of setting a sinking analog input & I didn't want to leave anything to chance, lead times on everything is just crazy anymore I cant risk a burned input channel becasue I made a mistake.

 

 

[kratmel]

Hi,

I'm wrong with PT100. Yes all jampers to B - is OK (except 11) for 2 termocouple and 2 current inputs for transmitters.

Than you setup 4 sensor to Samba.  You try to run only temperature mesurement or run PID loops?