Configured for mechanical relay dry contact actuation in CENTUM VP/CS 3000 FIO subsystems, the Yokogawa SARM55C (ARMS5C Mechanical Relay Contact Output Module) provides direct electrical execution of up to 32 relay output points to field devices with selectable NO or NC contacts.
The module converts low-voltage 24 VDC internal signals into switched outputs capable of handling AC and DC loads. Dual-redundant wiring schemes are supported per 16-point segment, ensuring isolated channel operation and minimal cross-coupling. Relay contacts meet defined ON/OFF load ratings while maintaining insulation resistance above 10 MΩ and withstand voltage up to 2 kV AC between field terminals and chassis.
Suffix Breakdown & Model Matrix
SARM55C / ARMS5C refers to a fixed mechanical relay output board designation within Yokogawa FIO hardware. No additional suffix variants are defined in the provided dataset.
Hardware Specifications
Parameter
Specification
ModelBrand
Yokogawa SARM55C
Origin
Japan
Weight
approx. 2.2 kg
Dimensions
482.6 mm x 132.5 mm
OperatingTemp
0 degC to 50 degC
PowerConsumption
24 VDC, max 0.65 A internal circuit
Channel Capacity
32-point mechanical relay contact output
Contact Configuration
NO/NC selectable per channel
Maximum Load
250 VAC @ 2 A, 30 VDC @ 2 A, 125 VDC @ 0.1 A per point
Minimum Load
5 VDC @ 10 mA
Insulation Resistance
>= 10 MΩ at 500 VDC
Withstand Voltage
2 kV AC (field terminals to case), 500 V AC (power terminals to case), 2 kV AC (field to power terminals)
Yokogawa Process Output Channel Architecture
Channel-to-Channel Isolation and Redundant Output Domains
The SARM55C implements electrical segregation per 16-point output group to reduce interference between adjacent relay channels. Mechanical relay contacts are designed to maintain isolation between control signals and high-voltage switched loads, while dual-line redundant output segments allow for safe sequential activation without channel-to-channel cross-talk.
Frequently Asked Questions
Q: Can SARM55C relay outputs switch both AC and DC loads simultaneously? A: Each channel is rated individually; AC and DC loads can be handled but simultaneous connection of multiple voltage types to the same contact is not recommended. Refer to maximum load ratings per channel.
Q: Is the module suitable for hot-swap insertion in the backplane? A: Hot-swapping is not supported under live field conditions. De-energize both 24 VDC field and internal power before module removal to prevent contact arcing.
Q: How is output contact polarity managed for NO/NC selection? A: Each output point provides mechanical selection of normally open or normally closed operation via internal relay configuration, without external wiring changes.
Field Installation Guidelines
Ensure all 24 VDC field and internal power supplies are de-energized before connecting M4 terminal screws.
Route field cables separately from power distribution lines to avoid inductive coupling.
Verify insulation resistance of 10 MΩ minimum at 500 VDC prior to commissioning.
Tighten terminals according to industrial torque standards to prevent loose connections and intermittent switching.
Mount on standard 19-inch rack with proper grounding of chassis to maintain EMC compliance.
