Application Scenarios:

In a packaging machine control panel, the 505-4916A​ module is installed in a TI545 PLC rack. Its relay outputs directly drive the coils of motor contactors (240V AC) and pneumatic solenoid valves (24V DC) that control the machine’s conveyor belts and sealing jaws. The module’s ability to handle mixed voltage loads on the same card simplifies the electrical design. In a water treatment plant, the same module is used in a distributed I/O cabinet to control pump starters and alarm horns, leveraging the relay’s high isolation (1500V) to protect the PLC from voltage surges on the motor control circuits.

 

 

Parameter:

Parameter Category	Specification Details
Manufacturer P/N​	505-4916A​ (also seen as 505-4916-A)
Brand / OEM​	Siemens​ (formerly Texas Instruments, SIMATIC TI505 series)
Product Type​	Digital Relay Output Module​
Compatible System​	SIMATIC TI505 PLCs​ (e.g., TI525, TI535, TI545, TI565)
Number of Outputs​	16 independent relay channels​
Output Type​	Form A (SPST-NO)​ mechanical relay contacts
Contact Rating​	2 A @ 30 V DC / 125 V AC​ (resistive load)
Maximum Voltage​	250 V AC / 30 V DC​
Load Type​	AC/DC resistive, inductive, lamp loads
Isolation Voltage​	1500 V AC​ (channel to logic/backplane)
Response Time​	ON: ≤ 10 ms, OFF: ≤ 10 ms
Status Indication​	16 green LEDs​ (one per channel)
Internal Power​	+5 V DC from backplane (logic power)
Connection​	Removable screw terminal block​
Operating Temp​	0 °C to +60 °C​
Status​	Discontinued (Legacy Product)​

 

 

 

Technical Principles and Innovative Values:

• Innovation Point 1: Universal Load Switching with High Isolation:​ Unlike transistor output modules that are limited to DC voltages, the 505-4916A​ utilizes electromechanical relays​ that provide galvanic isolation​ between the PLC’s logic circuit (5V DC) and the load circuit (up to 250V AC). This allows a single module to control a mix of AC and DC loads​ (e.g., 240V AC motor contactors and 24V DC solenoid valves) simultaneously without requiring external interposing relays. The 1500V isolation barrier​ protects the sensitive PLC backplane from high-voltage transients and ground loops common in industrial environments.
• Innovation Point 2: True “Dry Contact” Output:​ The relay contacts in the 505-4916A​ are true dry contacts​ (Form A). This means there is no leakage current​ when the output is in the OFF state, a critical feature for controlling sensitive devices or circuits where even micro-amperes of leakage could cause unintended activation (e.g., in safety monitoring circuits or latching relay logic). This contrasts with solid-state outputs (triacs/transistors) which typically have a small off-state leakage current.
• Innovation Point 3: Legacy System Longevity:​ As part of the SIMATIC TI505 series, this module was designed for long-term reliability​ in harsh conditions. The use of robust mechanical relays (with an electrical life of approximately 100,000 operations at rated load) ensures that systems installed decades ago can continue to operate with minimal maintenance. The module’s design prioritizes ease of troubleshooting​ with per-channel LEDs, allowing maintenance technicians to quickly identify faulty outputs without needing a programming device.