UPG_POC Focus Control
Normally the interface board for 9289 based steppers comes with a built in POC (Programmable Offset Control). This allows
for focus control in steppers that support the POC option. On older steppers, that use a 9280 interface chassis, the POC driver has to be added
using this UPG_POC product. The UPG_POC comprises a single channel 12-bit analog-to-digital converter (Z-axis feedback),
a single channel 12-bit digital-to-analog converter (focus voltage) and a single channel of digital I/O (lock/unlock the focus column).
Steppers of the vintage that use a 9280 interface chassis may use PFC
(stepper motor control) for focus instead of POC (voltage control).
UPG_POC : POC Driver