Description

Yokogawa ACM12 S1 Communication Module

Configured for serial data communication in Yokogawa control networks, the Yokogawa ACM12 S1 (ACM12 Communication Module) provides direct physical/electrical execution of RS-422 and RS-485 data exchange. The module supports one communication port with selectable point-to-point or multipoint topology, half-duplex transmission, asynchronous start-stop synchronization, and communication rates up to 19200 bps.

Suffix Breakdown & Model Matrix

The supplied documentation identifies the module as ACM12 S1. No official suffix decomposition or option matrix is provided in the source material; therefore, no further suffix interpretation is included.

Hardware Specifications

Parameter	Specification
Model	ACM12 S1
Brand	Yokogawa
Origin	Japan
Product Type	RS-422 / RS-485 Communication Module
Interface Port	1 Port
Communication Protocol	RS-422 or RS-485
Connection Type	Point-to-Point (RS-422), Multipoint (RS-485)
Communication Mode	Half-duplex
Synchronization	Start-stop synchronization
Communication Speed	1200 / 2400 / 4800 / 9600 / 19200 bps
Transmission Code	ASCII / Binary
Character Length	7 bit or 8 bit
Stop Bit Length	1 bit or 2 bit
Parity Check	None / Odd / Even
Signal Reception After Transmission	1 ms
Maximum Transmission Distance	1200 m total cable length
Installation Method	Communication Module Nest
Module Compatibility	Cannot be combined with ACF11; ACM11 can be combined with ACM12
Wiring Requirement	3-pair shielded cable or AKB161 connection cable
Connection Method	6-pole terminal, M4 screw connection
Power Consumption	1.0 A @ 5 VDC
Dimensions	Approximately 215 mm x 46 mm x 160 mm
Weight	Approximately 0.80 kg

Channel Isolation and DCS Communication Characteristics

Within process control architectures, the ACM12 functions as a serial communication interface between host control equipment and external field devices. The module supports ASCII and binary transmission formats while permitting configuration of parity, character length, and stop-bit parameters to match connected equipment requirements.

For RS-485 multipoint installations, shield continuity, grounding practice, and line termination must be coordinated across the communication segment to maintain signal integrity over cable distances up to 1200 m. The module provides configurable communication parameters suitable for integration with serial instruments, analyzers, controllers, and legacy DCS subsystems.

Frequently Asked Questions

Q: Does the ACM12 support both RS-422 and RS-485 communication standards?
A: Yes. The module supports one selectable communication port operating as either RS-422 or RS-485.

Q: Can the ACM12 operate in full-duplex mode?
A: No. The supplied specification identifies half-duplex communication mode only.

Q: Are there installation restrictions with other communication modules?
A: Yes. The documentation states that ACM12 cannot be combined with ACF11. ACM11 can be combined with ACM12 within the specified installation arrangement.

Field Installation Guidelines

• Install the module only in the designated Communication Module Nest location.
• Verify compatibility with adjacent modules before installation.
• Use shielded communication cable as specified by Yokogawa documentation.
• Route serial communication wiring separately from high-voltage power conductors to reduce electromagnetic interference.
• Bond cable shields according to site grounding standards and system design requirements.
• Tighten M4 terminal connections to the manufacturer's recommended torque specification.
• Confirm baud rate, parity, character length, and stop-bit settings are identical at both communication endpoints before commissioning.
• For RS-485 multidrop networks, apply appropriate network termination and address configuration according to the connected device requirements.

Specifications

• Brand: Yokogawa

Advantages

• High reliability in industrial environments
• Supports continuous operation
• Compatible with major PLC/DCS systems