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Synchronizing multiple wavebooks – Measurement Computing WaveBook rev.5.3 User Manual

Page 76

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There are two advantages of seamlessly supporting multiple WaveBooks in one system. First, is the ability

to expand beyond the 72 channel capacity of a single WaveBook. Second, if the per-channel sampling rate

of a single WaveBook system is inadequate, then additional WaveBooks can provide more bandwidth per

channel. For example, a 16 channel, single-WaveBook/516E system with one WBK option provides a

maximum bandwidth of 62.5 kHz/channel, i.e., 1M divided by 16. Instead, a sampling rate of

125 kHz/channel could have been achieved by using one WaveBook/516E connected to one slave

WaveBook/516A. This new “per-channel” sampling rate was calculated as follows:

1 MHz divided by 8 equals 125 kHz/channel.
The most common and highest-performance Ethernet connection for WaveBook/516E and for WBK25 is

achieved via a dedicated, point-to-point Ethernet link between the PC and the unit’s Ethernet port. Data

transfer rates in this configuration will accommodate continuous, 1 Mreading/s transfers from the

WaveBook to the PC.
With an enterprise-wide Ethernet network connection, any number of WaveBooks can be connected to the

network. Enterprise-wide Ethernet networks are typically shared amongst a large number of devices. In

such a scenario, the data transfer rates from the WaveBook are dependent on other network traffic at the

time of data transfer.

If you need to have continuous, 1 Mreading/s transfers from the WaveBook, you should

avoid connecting WaveBooks to an enterprise-wide Ethernet network. However, to

improve the data transfer performance of WaveBooks that are connected to such a

network, a WBK30 memory option should be installed. Contact the factory for

additional information.

Up to three WaveBook/516A or WaveBook/512A units can be attached to the three Expansion Ports of a

WaveBook/516E or WBK25. This application is useful when the channel requirements exceed the 72

channel capability of one WaveBook. It is also useful when the per-channel bandwidth exceeds that which

could be accomplished by a lone WaveBook, or if multiple time bases are required.
Note: In multiple WaveBook applications, the system can appear to the user as one large, synchronous

system. However, a system composed of many WaveBooks can be configured as several

independent systems, and with each system having its own triggering and sampling rates.

The parallel expansion ports on a WaveBook/516E can also be used to attach WBK40 thermocouple

modules and/or WBK41 Multi-Function modules. The units are detailed in the WBK Options User’s

Manual (p/n 489-0902). A PDF version of the document is included on the data acquisition CD. Note that

the SYNC signal on an “A” or “E” Series WaveBook can connect to a SYNC port theWBK40 or WBK41,

ensuring that both A/Ds will operate in synch.
A large WaveBook system can be configured with one Ethernet link to a PC, and could consist of, for

example either of the following two scenarios. In each case the WaveBook was expanded to its maximum

72 channel capacity, for a total system capacity of 288 high-speed channels.

288 Channel System, Example 1

216 Channel System, Example 2

WaveBook/516E (“Master” Unit) Connected to Ethernet

WaveBook/516A (Expansion Port 1, “Slave” Unit)*

WaveBook/516A (Expansion Port 2, “Slave” Unit)*

WaveBook/516A (Expansion Port 3, “Slave” Unit)*
*Expansion Ports are on the WaveBook/516E.

WBK25 Ethernet Interface Module Connected to Ethernet

WaveBook/516A (Expansion Port 1, “Master” Unit)**

WaveBook/516A (Expansion Port 2, “Slave” Unit)**

WaveBook/516A (Expansion Port 3, “Slave” Unit)**
**Expansion Ports are on the WBK25 Interface Module.

Any one of the 3 WaveBooks can be designated as the

Master Unit, and the other two as Slave Units.

Synchronizing Multiple WaveBooks

WaveBook software establishes one of the system’s WaveBooks as a “master” unit and

the others as “slaves” units. Master WaveBooks can run at the full 1-MHz aggregate

sampling rate. Slave WaveBooks must have 1 µs of unassigned sampling time in the scan

group. Note that some trigger modes are not supported in multi-WaveBook systems.
Additional information regarding synchronization is provided on page 4-23.

4-6 WaveBook Operation Reference

897895

WaveBook/512A, /516, /516A, /516E