Sensing

PS2-04-S Hardware Overview

The PS2-04-S is a sensing version of the PS2-04-A. In addition to sensing, it has the same capabilities as the PS2-04-A, and generally the same form factor and interface. However, the front panel of the PS2-04-S is slightly different from the PS2-04-A. Each channel has three connections instead of one - a HV output connection (#), a ground connection (#G), and a sensing connection (#S).

Connections

Sensing-enabled actuators should be connected to the PS2-04-S as shown below. The red HV wire should connect to the high voltage output (#), and the other two wires should connect to the ground (#G) and sensing (#S) connections. The ground and sensing connections are interchangeable, but the HV connection is not.

Reading Sensing Values

The sensing value on each channel of the PS2-04-S is a voltage reading between 0 and 3.3V. The meaning of this value will depend significantly on the geometry of the actuator used, and we recommend creating a calibration curve to translate this value into something meaningful for your application. It can be read via an external instrument using the HDMI port on the front of the device, or via the software API.

Via Hardware

The sensing value can be read via an external instrument, such as oscilloscope or data acquisition system, by connecting to the HDMI port on the front of the device. When using the PS2-04-S, please note that the HDMI connector has a different pinout than for the PS2-08-A. The pinout for the PS2-04-S is as follows:

 

Pin	Description	Pin	Description
10	Channel 3 Sensing	9	Channel 2 Sensing
11	Ground	8	Channel 1 Sensing
12	Ground	7	Channel 4 Sensing
13	Ground	6	Channel 1 Voltage
14	Ground	5	Channel 2 Voltage
15	Ground	4	Channel 3 Voltage
16	Ground	3	Channel 4 Voltage
17	Ground	2	Rail Voltage
18	Ground	1	Rail Current
19	Ground	20	Ground

Via Software

The channels of the PS2-04-S work in the same way as the PS2-04-A, but have an additional v_sense topic available for reading the sensing state. The v_sense topic may be read using the chX.ask() or chX.echo() commands. For example:

import ardi                 # import the ardi library
psu = ardi.autoconnect()    # connect to the first device found
ch1 = psu.channels['ch1']   # bind the first channel to the variable ch1
ch1.ask('v_sense')          # print the current sensing value of ch1
ch1.echo('v_sense')         # continuously print the current sensing value of ch1