NFDV551-P11

The Yokogawa NFDV551-P11 is a 32-channel digital output module for the STARDOM FCN control system. It provides isolated 24 VDC transistor outputs for switching external field loads through current-sink output circuits. The module supports individual ON/OFF control, output status monitoring, and configurable output fallback behavior for handling controller or communication-related fault conditions.

Functional Description

The NFDV551 provides 32 digital output channels for transmitting discrete control commands from the FCN controller to external field devices. Typical connected loads include DC interface circuits, indicator devices, and other compatible 24 VDC control loads.

Its current-sink output arrangement switches the load current through the output circuit toward the common negative reference. This requires the external load and field power supply to follow the specified wiring polarity.

Output Characteristics

The module uses isolated transistor output circuits, with the common negative connection arranged in groups of 16 channels. This arrangement separates the two output groups electrically and defines the common wiring requirements for field connections.

The output status function reports the ON/OFF state of the output channels. The specified status output response time is 3 ms or less. This value refers to status output response, not necessarily the complete response time of the controller-to-field control loop.

Output Fallback Function

The NFDV551 supports three output fallback settings:

• HOLD: Retains the current output states when the fallback condition is triggered.
• OFF: Resets all output channels to OFF.
• NO: Performs no fallback action.

The fallback setting applies to all channels together rather than allowing a separate fallback selection for each channel. The selected behavior should be checked against the process requirements before commissioning.

Technical Specifications

Parameter	Specification
Model	NFDV551-P11
Brand	Yokogawa
Product Type	Digital Output Module
Control System	STARDOM FCN
Number of Output Channels	32
Rated Applied Voltage	24 VDC
Load Voltage	24 VDC
Rated Load Current	50 mA
Maximum Load Current	100 mA/channel at 26.4 V
Field Power Supply Range	20.4-26.4 V
Output Format	Current sink
Maximum Output ON Voltage	2 VDC
Maximum OFF-State Leakage Current	0.1 mA
Output Isolation	2 kVAC between output signal and system
Common-to-Common Withstand Voltage	500 VAC
Output Common Configuration	Negative common, every 16 channels
Output Status Function	ON/OFF status indication
Output Status Response Time	3 ms or less
Output Fallback	HOLD / OFF / NO
Maximum Current Consumption	700 mA at 5 VDC
Field Supply Current Consumption	60 mA at 24 VDC
External Connection	Pressure-clamp terminal or 50-pin MIL connector cable
Weight	0.2 kg

Installation and Connection Considerations

The module supports pressure-clamp terminal connections and 50-pin MIL connector cables. Select the connection arrangement according to the actual terminal hardware and wiring configuration.

The 32 outputs are divided into two groups of 16, each with a negative common. Observe the specified common connections and field supply polarity when wiring external loads. The maximum channel current and field supply voltage must remain within the module's electrical ratings.

Frequently Asked Questions

Q: How many digital output points does the NFDV551-P11 provide?

A: It provides 32 isolated 24 VDC transistor output channels. The outputs use a current-sink configuration and are arranged in two groups of 16 channels.

Q: What happens to the outputs when a fallback condition occurs?

A: The module supports HOLD, OFF, and NO fallback settings. HOLD retains the existing output states, OFF resets all channels, and NO performs no fallback action. The setting applies to all channels together.

Q: Can the NFDV551-P11 drive AC loads directly?

A: No. Its output circuits are specified for 24 VDC field loads. AC loads require an appropriate external interface or switching device selected according to the load and control circuit requirements.

---