Measurement Specialties USB-1616HS-2 Setpoint configuration, Using the setpoint status register

USB-1616HS-2 User's Guide Functional Details

Setpoint configuration

You program all setpoints as part of the pre-acquisition setup, similar to setting up an external trigger. Since each setpoint acts on 16-bit data, each has two 16-bit compare values: a high limit (limit A) and a low limit (limit B). These limits define the setpoint window.

There are several possible conditions (criteria) and effectively three update modes, as explained in the following configuration summary.

Set high limit

You can set the 16-bit high limit (limit A) when configuring the USB-1616HS-2 through software.

Set low limit

You can set the 16-bit low limit (limit B) when configuring the USB-1616HS-2 through software.

Set criteria

ƒInside window: Signal is below 16-bit high limit and above 16-bit low limit.

ƒOutside window: Signal is above 16-bit high limit, or below 16-bit low limit.

ƒGreater than value: Signal is above 16-bit low limit, so 16-bit high limit is not used.

ƒLess than value: Signal is below 16-bit high limit, so 16-bit low limit is not used.

ƒEqual to value: Signal is equal to 16-bit high limit, and limit B is not used.

The equal to mode is intended for use when the counter or digital input channels are the source channel.

You should only use the equal to16-bit high limit (limit A) mode with counter or digital input channels as the channel source. If you want similar functionality for analog channels, then use the inside window mode

ƒHysteresis mode: Outside the window, high forces output 2 until an outside the window low condition exists, then output 1 is forced. Output 1 continues until an outside the window high condition exists. The cycle repeats as long as the acquisition is running in hysteresis mode.

Set output channel

ƒNone

ƒUpdate FIRSTPORTC

ƒUpdate DAC

ƒUpdate timerx

Update modes

ƒUpdate on True only

ƒUpdate on True and False

Set values for output

ƒ16-bit DAC value, FIRSTPORTC* value, or timer value when input meets criteria.

ƒ16-bit DAC value, FIRSTPORTC* value, or timer value when does not meet criteria.

*By default, FIRSTPORTC comes up as a digital input. You may want to initialize FIRSTPORTC to a known state before running the input scan to detect the setpoints.

When using setpoints with triggers other than immediate, hardware analog, or TLL, the setpoint criteria evaluation begins immediately upon arming the acquisition.

Using the setpoint status register

You can use the setpoint status register to check the current state of the 16 possible setpoints. In the register, Setpoint 0 is the least-significant bit and Setpoint 15 is the most-significant bit. Each setpoint is assigned a value of 0 or 1.

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