danw
Lifetime Supporting Member
I'm not an A-B guy, but I doubt A-B's A/O card in its high end PLC line can not handle a zero ohm load.
A 4-20mA output regulates the current in the circuit up to a maximum load, typically a load spec'd from 500 to 1200 ohms.
Industrial analog outputs can regulate current in a zero ohm load. Zero ohms in a 4-20mA circuit is NOT a short across a power supply, it's part of current regulated circuit (power supplies are voltage regulated, not current regulated).
It is entirely feasible to take the load all the way to zero ohms for a regulated current analog output without a negative consequence, which includes the low resistance of a milliameter current input.
I don't have a solution, but the absence of a resistor load is not the issue.
A 4-20mA output regulates the current in the circuit up to a maximum load, typically a load spec'd from 500 to 1200 ohms.
Industrial analog outputs can regulate current in a zero ohm load. Zero ohms in a 4-20mA circuit is NOT a short across a power supply, it's part of current regulated circuit (power supplies are voltage regulated, not current regulated).
It is entirely feasible to take the load all the way to zero ohms for a regulated current analog output without a negative consequence, which includes the low resistance of a milliameter current input.
I don't have a solution, but the absence of a resistor load is not the issue.