Module A-170 contains two separate slew limiters, also known as portamento controllers or integrators. The first SL has just one joint control, which sets both rise and fall times (c. 0 ...10 sec). The second SL has separate controls for rise and fall times, and can therefore be used as a simple AR envelope generator. Over and above this, you can set the overall range for these parameters, with a three-position switch, as on the full ADSRs.

Both slew limiters have two LEDs each, to show the state of the rising and falling voltages.