ABB RMC-100 - Analog Output Calibration; Connecting Calibration Equipment for AO

2105552MNAE | RMC-100 | 153
7.2 Analog output calibration
Calibration of the analog output (Analog Output, AO) ensures that the output signal matches the
requirements of the external device. External devices can connect to the AO in sink or source mode.
AO calibration measures the output signal for either mode of connection and assigns the appropriate
engineering units to the signal range.
Figure 7-38: AO connection modes
IMPORTANT NOTE:
Verify that the signal type of the external device is compatible with the
controller AO. The AO can provide 4
-20 mA output through the sink and source pins. For more
details on the AO specifications, see section
2.2.3.2 Analog output.
7.2.1 Connect the calibration equipment
The calibration requires only an ammeter or multimeter capable of measuring electrical current in
milliamps (mA). The AO signal is measured with or without the external device attached to the AO.
When the AO has no external device (no load) the ammeter connects based on the mode, either
across the source and ground pins, or across the sink and ground pins.
Connect the ammeter in series with the device to measure the AO with the external device attached
(with load).
IMPORTANT NOTE:
The procedures in this manual describe the calibration for the no-
load option.
Contact technical support to calibrate with the external device attached
.
7.2.1.1 No load connected to the AO
To connect the ammeter or multimeter only:
1. Power off the RMC.
2. Disconnect all the wires from the external device.
3. Connect the ammeter or multimeter to the external device’s wire ends (Figure 7-39
). Observe
the polarity and connect to the correct wire: positive probe to the source (SRC) or sink (SNK)
signal wire, and negative probe to the negative or ground (GND) wire.
PWR SNK SRC GND
+
-
AO
1
1 2 3 4
PWR SNK SRC GND
+
-
AO
1
1 2 3 4
Source mode
Sink mode
External
Device
External
Device