The A-170 contains two different slew limiters also known as portamento controllers or integrators.
The first slew limiter has just one joint control, which sets both rise and fall times (0 to 10 seconds).
The second slew limiter 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 ADSR’s. Both slew limiters have two LED’s each, to show the state of the rising and falling voltages.