Emerson 3AODO8 Field Installation Manual page 8

Emerson FB3000 RTU 8-Channel Output Module Field Installation Guide
D301917X012
October 2022
The figure, below, shows how to wire the analog output.
In the figure, AO_4 is configured for current output mode and is shown connected to an external
current field device. AO_7 is configured for voltage output mode and is shown connected to an
external voltage field device.
When configured as an AO, the ground pin of each AO is tied internally to all other AOs on the
module; they share a common internal ground regardless of whether they are configured for
current mode or voltage mode.
Analog Output (AO) Wiring
AO channels are read back to check the health of the AO:
Voltage outputs are verified to be within 30% of programmed values.

Current outputs are not verified, but the firmware reports an open on a current output as an

overrange AO, and a short on a current output as an under-range AO.
 The actual values read back are unavailable to the user and these checks are made internal to
the firmware.
Notes on Calibrating Analog Outputs
You calibrate the AO using FBxConnect software.

When calibrating the AO in voltage mode, you must calibrate each AO channel with the actual

load connected at a constant load impedance to meet performance specifications; otherwise
the calibration is invalid.
For voltage mode, the minimum load impedance driven by any AO is 1000 ohms.

For current mode, the minimum load impedance driven by any AO channel to allow detection

of a short-circuit is 40 ohms. If the load impedance is less than 40 ohms, the firmware detects a
short circuit even though it might not exist. The maximum load impedance in current mode is
500 ohms.
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