level transmitter problem

hello every one

i have problem with level transmitter direct mount on open tank ( transmitter depend on pressure )

when i connect  supply ( 24 vdc  comes from AI module form ET200 ) to transmitter , the voltage drop to 14 vdc and transmitter not working

when i remove transmitter from tank and connect supply to it , it is working proprely

can any one help me

thank you

 thank you for your reply

danw

The analog input resistance to whatever the current loop hooks up to can drop signficant voltage.  A 250 ohm resistor drops 1V at 4mA, 5V at 20mA.

On the bench, a 24.0Vdc power supply will measure 23.0 volts across the (+) and (-) terminals, dropping 1V at 4.0mA across a 250 ohm resistor in the loop.

It would take 500 ohms of loop resistance at 20mA (500ohms * 0.20A = 10.0V) to drop 10V to a measured 14 volts.   Or 2500 ohms to drop 10V at 4mA.

What else has been wired into the loop besides the power supply and the transmitter?

14 volts at the transmitter terminals should turn the transmitter on and make it work according to the spec sheet: 10.5Vdc minimum voltage for lift-off.

Assuming the power supply can drive another 21ma load, I suspect there's a combination of wiring at the tank and/or an excessive load that is affecting the transmitter.

 

 What else has been wired into the loop besides the power supply and the transmitter?

no thing

14 volts at the transmitter terminals should turn the transmitter on and make it work according to the spec sheet: 10.5Vdc minimum voltage for lift-off

transmitter is blinking all time and not working properely

i tried another transmitter out off tank and it was working from last 24 hours

the transmitter on the tank is new one , this is the first use of it

is the electric motor of the tank and pumps maybe the reason of high resistance ?

dear eng.abo hekmat..

I think u didnot gave full information about your level transmitter loop , Can u explain more please?!

Siemens level transmitter ( 2 wire type) (24vdc)  depend on pressure for measuring, mounted on  stanless steel  tank with 3" flange

It is connected with analog module of ET200 by 4 wire cable ( 2 wire used and 2 wire redundancy) 

When I supply it on the tank, it's not working or some times worked for period of time and then stop ( voltage drop to 14 vdc and transmitter start blinking) 

I tried it out of tank, it's worked good and not stopped

what is about the connections on the ET200 Module ?
what is the type of configuration from below (A- B-C-D) u have chosen for your situation?

stevano

what is about the connections on the ET200 Module ?
what is the type of configuration from below (A- B-C-D) u have chosen for your situation?

i chose  ( D ) because its 2 wire transmitter