Where is the ladder logic timer's Q output for the Siemens LOGO! PLC?

The Siemens LOGO! Programmable Logic Controller (PLC) may be programmed in Ladder Diagram (LD) or Function Block Diagram (FBD) using the LOGO! Soft Comfort software.

Many LD programming environments present the timer’s Q output as an extension of the block. This is not true for the LOGO. As seen in Figure 1, there are no right-hand connections to the block.

Figure 1: Siemens LOGO! ladder logic program featuring a time on delay timer.

To use the timer’s output, we must instantiate a contact and point it to the appropriate timer. An example is shown in Figure 2 where a normally open contact (red highlights) is being configured to use the T001 timer’s output.

Figure 2: The red highlighted contact is being configured to respond to the warmup timer.

Please let us know if you have any questions about the Siemens LOGO PLC. Recommend a new thread for your questions unless you would like to know more about the timers as programmed in ladder logic.

Sincerely,

Aaron

Related Information

Please follow these links to related and useful information:

About this author

Aaron Dahlen, LCDR USCG (Ret.), serves as an application engineer at DigiKey. He has a unique electronics and automation foundation built over a 27-year military career as a technician and engineer which was further enhanced by 12 years of teaching (interwoven). With an MSEE degree from Minnesota State University, Mankato, Dahlen has taught in an ABET-accredited EE program, served as the program coordinator for an EET program, and taught component-level repair to military electronics technicians.