NFAP135-S01

The Yokogawa NFAP135-S01 is an 8-channel pulse input module for the STARDOM FCN/FCJ control platform. It receives contact ON/OFF signals, voltage pulses and current pulses from field transmitters. Each input channel is isolated from the system and from the other channels, allowing pulse signals from different field devices to be acquired independently.

Pulse Input Function

The NFAP135 supports five input modes to accommodate different pulse transmitter configurations:

• Dry contact pulse using an open-collector contact.
• Dry contact pulse using a relay contact.
• Voltage pulse input.
• 2-wire transmitter current pulse input (4-20 mA).
• 3-wire transmitter voltage pulse input.

For current pulse input, the incoming current signal is converted to voltage within the input circuit. This allows the module to accommodate different transmitter output arrangements without treating every signal as a conventional digital contact input.

Channel Isolation and Signal Conditioning

The eight input channels are individually isolated, with a specified withstand voltage of 500 V AC for 1 minute between the input and system, and between channels. This separation helps limit the transfer of electrical disturbances between field signal circuits.

The module also provides selectable shunt resistance and a configurable chattering-elimination filter. These settings must correspond to the selected input mode and transmitter characteristics.

Input Configuration and Wiring

The connection terminals and electrical settings depend on the selected input mode. The module uses INA, INB and INC terminals, with different terminal combinations for contact, voltage and current pulse signals.

Input Mode	Connection	Configuration
Open-collector contact pulse	INB-INC	12 V or 24 V transmitter supply
Relay contact pulse	INA-INB	12 V transmitter supply
Voltage pulse	INB-INC	12 V or 24 V transmitter supply
2-wire current pulse (4-20 mA)	INA-INB	200 or 500 ohm shunt resistance
3-wire voltage pulse	INA-INB-INC	12 V or 24 V transmitter supply

The transmitter supply is selectable between 12 V DC and 24 V DC. The corresponding current limiter values are 40 mA and 30 mA, respectively. A 500 ohm shunt setting imposes additional restrictions: no adjacent module may be installed, and the pulse input module must be used with no more than four inputs.

Technical Specifications

Parameter	Specification
Model	NFAP135-S01
Brand	Yokogawa
Product Type	Pulse Input Module
Number of Input Channels	8, individually isolated
Input Frequency	0 to 10 kHz
Maximum Frequency for Open-Collector Input	800 Hz
Minimum Input Pulse Width	40 us
Supported Input Signals	Contact ON/OFF, voltage pulse, current pulse
Transmitter Supply	Selectable 12 V DC / 24 V DC
Transmitter Supply Current Limit	40 mA at 12 V DC; 30 mA at 24 V DC
Shunt Resistance	Selectable: OFF, 200, 500 or 1000 ohm
Pull-up Resistance	68 kohm
Data Refresh Cycle	2 ms
Withstanding Voltage	500 V AC for 1 minute, input-to-system and channel-to-channel
Maximum Current Consumption	300 mA at 5 V DC; 400 mA at 24 V DC
External Connection	Pressure clamp terminal or MIL connector cable
Weight	0.3 kg

Power Supply Requirements

The NFAP135 requires a 24 V DC supply to the analog field power supply terminal of the power supply module when used in the FCN/FCJ system. Its maximum current consumption is specified separately for the 5 V DC and 24 V DC supply rails.

The transmitter power supply selection is independent of the module's system power consumption specification. The 12 V DC or 24 V DC setting must be selected according to the connected transmitter and the required input mode.

Frequently Asked Questions

Q: Can the NFAP135-S01 accept both contact pulses and 4-20 mA pulse signals?

A: Yes. The NFAP135 supports dry contact pulses, voltage pulses and 2-wire current pulse signals. For 4-20 mA current pulse input, the appropriate shunt resistance and INA-INB connection must be selected.

Q: Can all eight channels operate at 10 kHz?

A: The general input frequency specification is 0 to 10 kHz. However, the open-collector dry contact input mode is limited to 800 Hz. The minimum input pulse width is 40 us, so the transmitter signal must also satisfy this requirement.

Q: What should be checked when using a 500 ohm shunt resistance?

A: The 500 ohm setting has specific installation restrictions. No module may be installed adjacent to the NFAP135, and the pulse input module must be used with no more than four inputs.

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