Clock update in Modicon Quantum

[afoley]

My current project is using a Modicon Quantum to control the belts and various processes in a coal proccessing plant. Relatively standard stuff. I am using RSView as the HMI for the operator and to process some data for a daily report, again fairly standard. My problem comes when I try to set the PLCs clock time from within RSView. The system tags will transmit to the PLC, but the clock value will not change. Do I need to use SBIT to set one (or more) of the clock register's bits before it will allow a write, and if so, which one?

[Jim Dungar]

Yes, there are bits that need to be set, in order to start/set the clock.

The first 4x clock register is the control register. The bits are:
1 - clock values are being set
2 - clock values are being read
3 - all clock values have been set
4 - error

To set the clock the bit pattern should be: 10000000000000000
To use the clock the bit pattern should be: 01100000000000000

(this looks weird but Modicon counts bits 1-16 left to right)

[afoley]

Thanks, Jim.
Actually I discovered this last night during a trip to the project site. I had found the information on the bits in the Block Library Users Guide, but it realy told me nothing but the respective bits basic function, as you show above. A little trial and error showed me the bit patterns I needed to achieve, from there it was all downhill to setting the logic to accomplish it.