Texas Instruments Siemens 505-6208-A Analog Input Module
The 505-6208-A is an analog input module originally manufactured by Texas Instruments for the 505 series programmable controller (later supported by Siemens as the SIMATIC 505). This module provides 8 differential analog input channels, each individually configurable for voltage or current signals. It is designed for high-accuracy measurement of sensors such as pressure transmitters, thermocouples (with external transmitter), and flow meters in industrial environments.
Input Specifications
Number of channels: 8 (differential).
Input ranges (software selectable per channel): 0–10V, ±10V, 0–5V, ±5V, 0–20mA, 4–20mA.
Resolution: 12 bits (4096 counts).
Accuracy: ±0.2% of full scale at 25°C, ±0.5% over temperature range.
Input impedance: 250 Ω (current mode), >1 MΩ (voltage mode).
Maximum input: ±30V or ±30mA (non-destructive).
Isolation and Protection
Each channel is optically isolated from the backplane (1500 Vrms) and from each other. Common mode voltage range: ±10V. The module includes ESD protection (15 kV air discharge) and input filtering (RC 20 Hz cutoff). Overvoltage protection clamps inputs to ±24V via fast transient suppressors.
Data Conversion
An integrating ADC with 50/60 Hz noise rejection (selectable) performs conversion. The total scan time for all 8 channels is 100 ms (12.5 ms per channel). Data is presented to the CPU as 12-bit left-justified in a 16-bit word. For 4–20mA signals, the reading is scaled to 0–4095 (4mA = 0, 20mA = 4095). The module provides a built-in sensor supply (+15V, 50mA) for loop-powered transmitters.
Configuration
Configuration is performed via dip switches on the module or using SoftShop software (depending on firmware version). Switches set the module address (1–16) on the 505 backplane and select voltage/current mode per channel group (two groups of four). The module also supports configurable digital filtering (smoothing) from 0 to 10 samples.
Status LEDs and Diagnostics
Front panel LEDs: ACTIVE (green) indicates communication with CPU; FAULT (red) indicates input overrange or underrange; each channel has a yellow LED that blinks when data is being read. Diagnostic data includes channel open-circuit detection (for 4–20mA) and out-of-range alarms. These faults can be read from the CPU’s I/O map.
Power and Environment
The module draws 300 mA from the 5V backplane and 150 mA from the isolated 24V field supply (provided by the power supply module, e.g., 505-7000). Operating temperature: 0 to 60°C; storage: -40 to 85°C. Humidity: 10% to 95% non-condensing. Dimensions: 280 mm x 35 mm x 200 mm. Weight: 0.6 kg.
Compatibility
Works with all TI505 and Siemens 505 series CPUs: 545-1105, 555-1106, 565-1107, and 575-1108. It can be placed in any slot of a 505 rack (4-slot, 8-slot, or 16-slot). The module is not hot-swappable; the system must be powered off for installation or removal.
Typical Applications
Used in wastewater treatment plants (flow metering), power generation (temperature monitoring), and chemical batch processes (pressure and level). The 8-channel density saves rack space compared to 4-channel alternatives.
Maintenance and Spares
No periodic calibration is required, but recalibration can be performed using a precision source and the 505 service tool. Replacement terminal blocks (505-6285) are available. The module has no field-replaceable fuses; all protection is self-resetting.
Ordering Information
Part number: 505-6208-A (remanufactured unit). This module has been tested and verified against original Texas Instruments specifications. Manual reference: TI505 Analog I/O User Manual (Pub No. 3050420-01).
