| Counter Name | Width | Description | Notes |
| SI_counter | 24-bit | Scan Interval, which defines the interval between each scan. | Scan Interval = SI_counter / Time-base* |
| SI2_counter | 24-bit | Sampling Interval, which defines the interval between each sampled channel. | Sampling Interval = SI2_counter / Timebase* |
| PSC_counter | 24-bit | Post Scan Counts, which defines how many scans to be performed with re-spect to each trigger. | |
| Delay_counter | 16-bit | Define the delay time for scan after trigger. | Delay Time = (Delay_counter / Time-base*),Timebase*=40Mfor DAQ/DAQe/PXI-250x Series |
Table 4-4: Summary of Counters for Programmable Scan
The relationship between counters and acquisition timing is illustrated in Figure 4-2.
3 Scans.4 Samples per scan
(PSC\_Counter=3)
(Scan acquisition is performed in ascending sequence for enabled channels)
Figure 4-2: Timing for Scan
# Note:
1. The maximum A/D sampling rate is 400KHz for DAQ/DAQe/ PXI-250x Series therefore the minimum setting of SI2\_counter is 100.
2. The Scan Interval can not be smaller than the interval of data Sampling Interval multiple by the Number of channels per Scan, i.e.: SI\_counter >= SI2\_counter \* NumChan\_Counter.
# 4.1.5 Trigger Modes
# Post-Trigger Acquisition
Use post-trigger acquisition when users want to perform scans right after a trigger signal. The number of scans to be performed after the trigger signal is specified by the PSC\_counter, as illustrated in Figure 4.3. The total acquired data length = (number\_of\_channels\_enabled\_for\_scan\_acquisition) \* PSC\_counter.
# Delay Trigger Acquisition
Use delay trigger when users want to delay the scan after a trigger signal. The delay time is determined by the Delay\_counter, as shown in Figure 4-4.
The counter counts down on the rising edges of Delay\_counter clock source after the trigger signal. When the count reaches 0, DAQ/DAQE/PXI-250X SERIES starts to perform the scan. The acquired data length = (number\_of\_channels\_enabled\_for\_scan\_acquisition) \* PSC\_counter. The Delay\_counter clock source can be software selected from Internal 40MHz Timebase, external input (AFI-1), or General Purpose Timer/Counter Output 0/1.
# Post-Trigger or Delay-trigger Acquisition with Retrigger
Use post-trigger or delay-trigger acquisition with retrigger when users want to perform repeated scans with respect to the repeated triggers. Figure 4-5 illustrates an example. Two scans are performed after the first trigger signal, and then wait for the next trigger signal. When the trigger signal occurs, it performs 2 more scans.
When retrigger function is disabled, only one trigger signal would be accepted after retrigger.
Note: Retrigger signals asserted during scan process will be ignored.
Figure 4-3: Post Trigger
(NumChan\_Counter=4.PSC\_Counter=3)
Figure 4-4: Delay Trigger
Figure 4-5: Post Trigger with Retrigger
# 4.1.6 Bus-mastering DMA Data Transfer
In programmable scan acquisition mode, all DAQ/DAQe/PXI series cards supports bus-mastering DMA data transfer. PCI bus-mastering DMA is necessary for high speed DAQ in order to utilize the maximum bus bandwidth. The bus-mastering controller controls the PCI bus when it becomes the master. Bus mastering reduces the size of the onboard memory and reduces CPU loading since data is directly transferred to the system memory with no host CPU intervention.
Bus-mastering DMA provides the fastest data transfer rate on a PCI bus. Once the analog input operation starts, control returns to your program. The hardware temporarily stores the acquired data in the onboard AD Data FIFO, then transfers the data to a user-defined DMA buffer memory in the computer. Note that even when the acquired data length is less than the Data FIFO, the AD data is not kept in the Data FIFO but rather directly transferred to the host memory by the bus-mastering DMA.
The DMA transfer mode is very complex to program. It is recommended that you use a high-level program library provided by the ADLINK driver to configure this card. By using a highlevel programming library for high speed DMA data acquisition, you convert through their specified counters. After the AD trigger condition is matched, the data will be transferred to the system memory by the bus-mastering DMA.
The PCI controller also supports the scatter/gather bus mastering DMA function that enables transfer of large amounts of data by linking all the memory blocks into a continuous linked list.
In a multi-user or multitasking OS, like Windows or Linux, it is difficult to allocate a large continuous memory block to do the DMA transfer. Therefore, the PCI controller provides the function of scatter-gather or chaining mode DMA to link the noncontinuous memory blocks into a linked list, allowing transfers of very large amounts of data without being limited by the fragment of small size memory. You may configure the linked list for the input DMA channel or the output DMA channel. Figure 4-6 shows a linked list that is constructed by three DMA descriptors. Each descriptor contains a PCI address, a PCI dual-address, a transfer size, and the pointer to the next descriptor. PCI address and PCI dual address cycle support 64-bit addresses which can be mapped into more than 4 GB of the address space. You can allocate many small size memory blocks and chain their associative DMA descriptors altogether by their application programs.
Figure 4-6: Linked List of PCI Address DMA Descriptors
In non-chaining mode, the maximum DMA data transfer size is 2M double words (8 MB). However, by using chaining mode-scatter/ gather, there is no limitation for the DMA data transfer size. You may also link the descriptor nodes circularly to achieve a multibuffered mode DMA.
# 4.2 D/A Conversion
DAQ/DAQe/PXI-250x Series offers flexible and versatile analog output scheme to fit users’ complex field applications. In order to take full advantages of DAQ/DAQe/PXI-250x Series, we suggest users carefully read the following con-tents.
# Architecture
There are up to 8-channel of 12-bit Digital-to-Analog Converter (DAC) available in the DAQ/DAQe/PXI-2502. Four D/A channels are packed into one D/A group, i.e., DAQ/DAQe/PXI-2502 contains two D/ A groups, and DAQ/DAQe/PXI-2501 has only one D/ A group.
Figure 4-7: Block Diagram of D/A Group
(Group B of DAQ/DAQE/PXI-2502 is identical to Group A shown above)
Figure 4-7 shows the D/A block diagram. DAC are controlled implicitly by CPLD and have their outputs updated only when digital codes for all enabled DA channels are ready and latched. This ensures D/A conversions to be synchronized for each channel in the same D/A group. Users can utilize this property to perform multi-channel waveform generation without any phase-lag.
# Hardware controlled Waveform Generation
FIFO is a hardware first-in first-out data queue, which holds temporary digital codes for D/A conversion. When DAQ/DAQe/PXI-250x Series operates in Waveform Generation mode, the waveform patterns are stored in FIFO, with 8K maximum samples. Waveform patterns larger than 8K are also supported by utilizing bus-mastering DMA transfer supported by PCI controller. Data format in FIFO is shown in Figure 4-8.
Note: 1) CH0, CH1, CH3 are used for Waveform Generation.
2) CH2 is disabled in this case.
3) FIFO Data are assigned to DAC in sequence: CH0,CH1,CH3.
Result
| Standard Function |
| <img src="images/c82d5344b66e0798d43a76d28a7804c4323bccccc8d901ea27a134604d820871.jpg"/> | Waveforms including sine wave, triangular wave, saw wave, ramp, etc., can be converted to Waveform LUT. Using larger waveform means trading maxi-mum output rate for lower harmonic distortion. |
| Arbitrary Function |
| <img src="images/3d13588d2689261b44547bb66f5284e32f9bb30383ff684fcaa4f47b69e773f8.jpg"/> | User defined arbitrary function without size limit can be generated. Users can also concatenate various standard functions of same length into one arbitrary function and setup piece-wise generation, so each standard function can be generated in sequence, with a user definable intermediate space. |
| Standard Function w. Frequency Variant |
| <img src="images/f5bb5b76d8e8504837e9f956e5c436feff61f55d7cd5e9d9979138b1274ac228.jpg"/> | Users can alter the frequency of generated waveforms by driving DAWR from external signal via AF0/AF1/SSI. The resultant updating rate should be kept within1MHz. In this demo, iterative generation is used. |
| Iterative Generation w. Intermediate Space |
| <img src="images/e9929b04c61830b72d0ef7c920c7da8186c096bd4cfe24aa0c21ba9ad6e92ac4.jpg"/> | Utilize DLY2_counter to separate consecutive waveform generations in iterative generation mode. In this demo, the original standard sine wave is repeated several times as specified in IC_counter, with intermediate space determined by DLY2_counter. |
| Piece-wise Generation |
| <img src="images/9ccdd2f2b0d481ec673a1100182e20bb8129034b22362ecc014a0cc76f804f59.jpg"/> | When the value specified in UC_counter is smaller than the sample size of waveform, the waveform is generated piece-wisely. The intermediate space between each piece is determined by DLY2_counter. In this demo, the UC_counter is set to 1/8 of the sample size of waveform. |
| Amplitude Modulated |
| <img src="images/7b49c29284d230cdfc311aee6a75a18ce7fc0cde21abd59d98bf2538e28e4c92.jpg"/> | When external D/A reference is used, applying sinusoidal voltage reference will result in an amplitude modulated (AM) waveform generation. Users can use one D/A channel to generate sine wave, loop it back to AOEXTREF_A/ B pin, and generate AM waveform by another D/A channel using external reference. All can be done in a single D/A group. |
| Frequency Modulated |
| <img src="images/49bfbaf0effeadc43aae94859f16d1e86a90c01699a75363ee42554c9717ace0.jpg"/> | By feeding AFI0/AFI1 with PWM source, pulse train from VCO, or any time-varying digital signal, DAQ/DAQE/PXI-250x Series is capable of generating frequency modulated (FM) waveform. Since all four channels are synchronized in a D/A group, precise quadrature waveform generation is guaranteed, provided the waveform are shifted 90-degree for the other channel. Phase difference of any degree can also be setup. Combined with external High-speed programmable Digital I/O card, Phase-Shift-Keying or Phase-Reversal-Keying can also be achieved. |
# Important Safety Instructions
For user safety, please read and follow all instructions, Warnings, Cautions, and Notes marked in this manual and on the associated device before handling/operating the device, to avoid injury or damage.
S'il vous plaît prêter attention stricte à tous les avertissements et mises en garde figurant sur l'appareil , pour éviter des blessures ou des dommages.
Read these safety instructions carefully.
Keep the User’s Manual for future reference.
Read the Specifications section of this manual for detailed information on the recommended operating environment.
The device can be operated at an ambient temperature of 50ºC.
When installing/mounting or uninstalling/removing device, or when removal of a chassis cover is required for user servicing:
Turn off power and unplug any power cords/cables.
Reinstall all chassis covers before restoring power.
To avoid electrical shock and/or damage to device:
Keep device away from water or liquid sources.
Keep device away from high heat or humidity.
Keep device properly ventilated (do not block or cover ventilation openings).
Always use recommended voltage and power source settings.
Always install and operate device near an easily accessible electrical outlet.
Secure the power cord (do not place any object on/over the power cord).
Only install/attach and operate device on stable surfaces and/or recommended mountings.
If the device will not be used for long periods of time, turn off and unplug it from its power source
Never attempt to repair the device, which should only be serviced by qualified technical personnel using suitable tools
A Lithium-type battery may be provided for uninterrupted backup or emergency power.
Risk of explosion if battery is replaced with one of an incorrect type; please dispose of used batteries appropriately.
Risque d’explosion si la pile est remplacée par une autre de type incorrect. Veuillez jeter les piles usagées de façon appropriée.
The device must be serviced by authorized technicians when:
The power cord or plug is damaged.
Liquid has entered the device interior.
The device has been exposed to high humidity and/or moisture.
The device is not functioning or does not function according to the User’s Manual.
The device has been dropped and/or damaged and/or shows obvious signs of breakage.
Disconnect the power supply cord before loosening the thumbscrews and always fasten the thumbscrews with a screwdriver before starting the system up.
It is recommended that the device be installed only in a server room or computer room where access is:
Restricted to qualified service personnel or users familiar with restrictions applied to the location, reasons therefor, and any precautions required.
Only afforded by the use of a tool or lock and key, or other means of security, and controlled by the authority responsible for the location.
# BURN HAZARD
Touching this surface could result in bodily injury. To reduce risk, allow the surface to cool before touching.
# RISQUE DE BRÛLURES
Ne touchez pas cette surface, cela pourrait entraîner des blessures.
Pour éviter tout danger, laissez la surface refroidir avant de la toucher.
# Getting Service
Ask an Expert: https://www.adlinktech.com/en/Askanexpert
# ADLINK Technology, Inc.
No. 66, Huaya 1st Road, Guishan District
Taoyuan City 333, Taiwan
Tel: +886-3-216-5088
Fax: +886-3-328-5723
Email: service@adlinktech.com
# Ampro ADLINK Technology, Inc.
6450 Via Del Oro, San Jose,
CA 95119-1208, USA
Tel: +1-408-360-0200
Toll Free: +1-800-966-5200 (USA only)
Fax: +1-408-600-1189
Email: info@adlinktech.com
# ADLINK Technology (China) Co., Ltd.
300 Fang Chun Rd., Zhangjiang Hi-Tech Park
Pudong New Area, Shanghai, 201203 China
Tel: +86-21-5132-8988
Fax: +86-21-5132-3588
Email: market@adlinktech.com
# ADLINK Technology GmbH
Hans-Thoma-Straße 11
D-68163 Mannheim, Germany
Tel: +49-621-43214-0
Fax: +49-621 43214-30
Email: emea@adlinktech.com
Please visit the Contact page at www.adlinktech.com for information on how to contact the ADLINK regional office nearest you.
[🔗 Link to the original document](.daq-daqe-pxi-250x-50m-12264-1000-10/daq-daqe-pxi-250x-50m-12264-1000-10.pdf)