General
Function
The Spectrum Controls’ 1756sc-IF8u Universal Input module for the 1756 system provides ControlLogix controllers with 8-channels of analog input capability:
- Per-channel selectable Voltage, Current, Resistance, RTD and Thermocouple input
- 16-21 bit resolution and user scaling, with IEEE 32 bit Floating Point data format
- 5 filter frequencies, per-channel selectable;
- update rates from 40ms to 1second (except for RTD/TC)
- Configurable process and rate alarms, and input data time-stamping
- Module-level fault detection (self-diagnosing)
- Full auto-calibration
Field Interface
- Input Types:
- Thermocouple B, C, E, J, K, N, R, S, T, with Spectrum CJC sensors (cold junction compensation)
- RTD PT 385/3916, N 618/672, NI 518, CU 426
- Resistance 250, 500, 1000, 2000, 3000, 4000 ohms
- Current 0-20 mA, 4-20 mA
- Voltage ±50mV, ±150mV, 0-5V, 1-5V, 0-10V, ±10V
- Over-voltage and over-current protection
- Selectable over-range and under-range detection and indication
- Selectable open circuit detection (wire-off) for most input types, short circuit for RTDs
- 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):
Data
The following module data types and tags are created by the AOP:
- Input Tag (23 bytes)
- Channel values and CJC sensor values.
- Status and Fault words.
- Timestamps
- Output Tag (0 bytes)
- Configuration Tag (396 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
- RPI = 100ms default, 10-750ms range
- 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
- Unlatch alarms
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: 210mA at 5VDC, and 75mA at 24VDC.
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