General
Function
The Spectrum Controls’ 1756-RMS-SC RMS Analog Input module for the 1756 system provides ControlLogix controllers with 8, isolated, independently configurable input channel pairs; one current, one voltage, to measure real power, apparent power, reactive power, and power factor:
- Per-channel-pair selectable voltage or current input
- 16-bit resolution scaled at PLC input (current and voltage)
- Voltage input range: each channel’s voltage provided by customer current transformer/load resistor
- Scan rate: 50 scans/second at 50 Hz; 60 scans/second at 60 Hz
- Configurable high/low voltage and current alarms, voltage/current clipping alarms, alarm latching, and input data time-stamping
- Module-level fault detection (self-diagnosing)
- Full auto-calibration
Field Interface
- Input Types
- Current transformer input ranges: 5 V RMS, 10 V peak at Range 1; 2.5 V RMS, 5 V peak at Range 2; 1 V RMS, 2 V peak at Range 3; 0.5 V RMS, 1 V peak at Range 4
- Over-voltage and over-current protection
- Selectable over-range and under-range detection and indication
- Field connector and cables
- Standard 36-pin removable terminal block; 1756-TBCH (screw) or 1756-TBS6H (press); ordered from Rockwell Automation; RTB mechanical keying.
- Refer to the module’s "Owner’s Guide” for recommended shielded twisted-pair cable, a list of standard pre-wired cables, and complete wiring recommendations and considerations.
Module Identity
The module Identity includes the following Device attributes ( refer to "EDS File” below):
Vendor ID: 58 | Vendor name: "SPECTRUM CONTROLS, INC." |
Product Type: 10 | Product Type Name: "8-Channel Isolated RMS Input" |
Product Code: 29 | Product Name: "1756-RMS-SC" |
Data
The following module data types and tags are created by the AOP:
- Input Tag (304 bytes)
- Channel values and nnnnn values
- Status and Fault words
- Timestamps
- Output Tag (224 bytes)
- Configuration Tag (292 bytes) - configurable through the AOP configuration tabs
Note
: IO Tags are updated by the controller asynchronous to its ladder-logic program scan. When "block integrity” of this data is important, the CPS ladder instruction can synchronously copy the data to other tags for use by application logic. Refer to the "Owner’s Guide” for recommended methods.Communication
1756 Backplane Communication
- Connected producer/consumer multicast IO communication
- Settable RPI (17 ms or greater)
- Support for multiple controllers, either "listen only” or multiple owners.
- Local chassis operation, or Remote chassis operation (over CIP network).
- Unconnected messaging from controller (MSG instruction) or from a CIP network client. Typical uses include:
- Reset or Reconfigure the module
NOTE
: Refer to detailed protocols and MSG examples described in the module’s "Owner’s Guide”, and examples in the module’s RSLogix5000 Sample Projects.Bus Power
From the 1756 backplane: 320 mA at 5 VDC, and 220 mA at 24 VDC.
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