Application Notes

EAP-032108

Converting Tank Level into Consumed Volume

We are utilizing a 2-wire flow rate transmitter and a current loop supply, M2DYS as combination. This time we’d like to add a 2-wire digital DC meter, model 6DV-B inserted on this loop. However, the output load resistance of the flow rate transmitter will exceed the limited 400 ohms if we installed the 6DV-B in series connection. Does M-System have some suitable solution?

The M2DYS has an input resistance 50 ohm to be linked to input terminal 4 and also 250 ohm between the terminal 5 and 8, therefore it has total 300 ohm as its input resistance. (See Table 1)

By short-circuiting terminals between 5 and 8, you can cancel the above-mentioned 250 ohm and then the total input resistance of the M2DYS will be reduced to be 50 ohm. You then be able to install the 6DV-B without problem. Please be aware that the above solution makes the monitor terminals (8 and 5) unusable and makes it not to comply with “smart transmitter”.