Special feature S05 on a West N6100 changed the function of the "Auto-Manual" key.
When this key was pressed in operator mode on a standard unit (without S05), the control switches from automatic PID to manual mode with bumpless transfer. The lower display then shows "Pxxx", where xxx was the last power output level set by PID. This power level is the initial value used in manual mode.
When this key was pressed in operator mode on a unit with special feature S05, pressing the Auto-manual key caused the control outputs to go straight to zero, i.e. it turned the power 'off'. The lower display showed "O OFF". Pressing the Auto-Manual key again returned it to normal automatic PID mode.
The N6100 is obsolete, and the special feature S05 is not available on the newer P6100. The West N6600 has this feature so the N6600 can often replace an N6100 S05 (but note the limited input and output types on the N6600 compared to the N6100).
If the special feature in not required, you can replace the N6100-xxxxxxxx-S05 product with the equivalent P6100- xxxxxxxx (without S05).
