Tri-Sen analog output low


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On my way into work to check out a Tri-sen TS 310 controller that doesn't want to output a full 20 ma signal.

Am being told all permissives were met for the "Over Speed Test" yet the controller will only produce 19.2 ma

This is a speed controller with 5 speed probes and a single valve output

Anyone recognize this problem?
Page 40 of the TS310 User Guide states that the voltage driving the output is 7 volts and that an output configured for 20mA max can drive a load up to 350 ohms.

An additional 15 ohms (365 ohms total) would limit the max output to 19.2mA.
What's your loop resistance? What's the AO current running into?

If the internal power supply droops below 7 volts, the droop could show up as an inability to drive whatever load is in the loop circuit.

A commercial loop isolator (4-20mA in/4-20mA out) typically drives 500 ohms if this AO is just plain feeble.

Curt Wuollet

Possibly a compliance voltage issue? If the load is too light for some reason there isn't enough voltage available to get to 20 ma. Or low applied voltage?