What is the difference between the ST42, KS250 and PT500, and which should I choose?
The ST42 is an in-panel DC motor driver that drives two motors independently; it carries 4 A per channel and 8 A in total, its speed and ramp are adjustable, and it has no AntiSwitch. The KS250 offers 12/24V, 15A continuous and 45A peak (5 s), IP45, built-in AntiSwitch, a ramp and speed setting with a pot. The PT500 is a programmable model with 12-24V, 30A continuous, 40A max (15 s), IP67 and independent AntiSwitch limits for both directions.
Three questions separate the three models: how many motors will you drive, how many amps do you draw, and where will it stop?
- ST42: Direction and on/off control for two independent motors, with adjustable speed and ramp. Driven by an RF receiver, a manual button or a panel signal. Intended for automatic doors/barriers, mini cranes, DC linear actuators and in-panel automation. It is rated for 4 A per channel and 8 A in total; in applications demanding more current, prefer the KS250 or PT500.
- KS250: 12/24V DC, 15 A continuous, 45 A peak (5 s), IP45, 120x40x46 mm, 110 g, 24 months warranty. Built-in AntiSwitch, soft start/stop ramp, IN1-IN4 digital inputs and IN5 analogue input.
- PT500: 12-24V DC, 30 A continuous, 40 A maximum (15 s), IP67. Independent AntiSwitch current limit for each direction (A1 and A2 pots), SPEED and RMP pots, A-D digital and E analogue inputs, programmable firmware that can be customised for the user.
Practical summary: if you will drive two motors independently and 4 A per channel is enough, the ST42; if you want up to 15 A on a single motor with automatic current-based termination, the KS250; if you need up to 30 A, outdoor use and custom operating logic, the PT500.
The full topic: DC Motor Driver Selection Guide