SDV531-S23/D4A00 S3

The Yokogawa SDV531-S23/D4A00 S3 is an 8-channel, 24 V DC digital output module for the ProSafe-RS safety control system. It converts output commands from the Safety Control Station (SCS) into discrete electrical signals for field devices. Its module-isolated output architecture separates the field output circuits from the system side, supporting discrete control of connected loads.

Functional Description

The SDV531 series provides 24 V DC digital outputs through eight channels. Each channel switches a discrete field signal according to the output data received from the safety control system. Typical connected loads include solenoid-operated devices and relay interfaces, subject to the module's electrical load specifications.

The module isolation separates the output signal circuits from the internal system circuitry. This arrangement helps limit the propagation of electrical disturbances between the field wiring and the control system.

Output Characteristics and Protection

The SDV531-S23 has a specific short-circuit response that distinguishes it from the SDV531-S13 version. When a short circuit occurs on the field side, the affected output channel switches OFF, while the other output channels are not described as being shut down by this channel-specific response.

After the short-circuit condition is cleared, the affected channel requires an Output Enable Operation. Until this operation is performed, the channel maintains its configured fail-safe output value. This behavior is important when checking application logic and recovery procedures in an existing ProSafe-RS installation.

Technical Specifications

Parameter	Specification
Model	SDV531-S23/D4A00 S3
Brand	Yokogawa
Product Type	Digital Output Module
System	ProSafe-RS
Number of Outputs	8 channels
Output Voltage	24 V DC
Output Format	Current source
Maximum Load Current	0.6 A per output line
Total Output Current	4.8 A
Minimum Load Current	35 mA
Load Resistance Range	40 to 685 ohms
Maximum Output Voltage Drop	1 V
Maximum Off-State Leakage Current	1.6 mA
Output Response Time	30 ms maximum
External Power Supply	24 V DC, +20% / -10%
External Power Supply Capacity	5 A
Module Isolation	Output signal lines to system
Withstand Voltage	2 kV AC for 1 minute (specified test configuration)
Internal Current Consumption	280 mA maximum at 5 V DC; 140 mA maximum at 24 V DC
Weight	0.28 kg
Dimensions	130 x 107.5 x 32.8 mm

Field Connection and Installation

The SDV531 supports different field connection arrangements depending on the terminal and cable configuration:

• Pressure-clamp terminal connection.
• MIL cable connection.
• Dedicated signal cable connection using the applicable interface arrangement.

The external 24 V DC supply powers the field output circuits. When selecting the field wiring, account for cable resistance, terminal-board resistance and the resulting voltage drop. Yokogawa specifies a maximum output voltage drop of 1 V, so the voltage available at the field load must be considered when checking the operating conditions.

Frequently Asked Questions

Q: What happens when an output channel experiences a field-side short circuit?

A: For the SDV531-S23, the affected channel switches OFF rather than shutting down all eight output channels. Once the fault is cleared, an Output Enable Operation is required to restore the channel to its application logic output.

Q: What external power supply does the SDV531-S23 require?

A: The module uses an external 24 V DC field supply with a permitted range of +20% / -10%. The specified supply capacity is 5 A, based on the rated load requirements.

Q: Can the SDV531-S23 directly drive field devices?

A: Yes. Its current-source outputs provide discrete 24 V DC signals for compatible field loads. Each output line must remain within the specified current and load-resistance limits, including load inrush current and field wiring resistance.

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