Dear All.

I am upgrading 25 year old TI plc to Step7.

The TI PLC is as follows:

5TI Expander



Model: 5TI-5500

Supply Volt: 102-132 VAC 47-63 HZ

Serial # : 15EX8510000491

Full load current: 0.75 A



5TI Sequencer



Model : 5TI-1031-1

Supply Volt : 102-132 VAC 47-63 HZ

Serial # : 81030077

Full load current : 0.75 A


I have the hard copy of TI Program.
I am facing Difficulty in understanding TMR & CTR in TI Program.
The TMR istruction is as follows:



The CTR instruction is as follows:



Kindly help me in finding out, how this timer and counter instruction is working

Which one is on-delay or off-delay timer??
Which one is up or down counter??

Your help regarding this matter will be highly appreciated.

Regards,
Tariq