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Order These Products direct From The Manufacturer At: We No Longer Sell Or Stock These Items. Continue Below for Product Information Only.
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SM4000 Series |
PCI Relay Scanner/Multiplexer |
SM4020 |
20 Channel |
SM4022 |
20 Channel, Instrumentation |
SM4040 |
40 Channel |
SM4042 |
40 Channel, Instrumentation |
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Features
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Uncompromising PerformanceThe SM4000 family of start-of-the-art, high density relay scanners/multiplexers are designed to compliment Signametrics' line of high-end DMMs with suitable precision switching capabilities. Utilizing an on-board Micro-controller, the SM4000 series is an intelligent switching product, particularly suitable for demanding test applications. The SM4000 can be configured on-the-fly to handle 2, 4 and 6 wire guarded measurements. The very low thermal-offset, leakage and capacitance make the SM4000 ideal for switching precise signals, and unlike currently available products, it will not degrade measurements. To top the SM4000 series superior functionality and switching performance, it features an unparalleled built-in self-test capability that checks for actuation time, contact bounce and contact failure. |
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SM4000 Series ArchitectureThe SM4000 series employs up to 4 differential switching groups of 10:1 . Each group features a "Tree Relay" that isolates a group when not in use. The "Tree Relay" architecture minimizes the overall capacitance and leakage as seen by the stimuli or measurement instruments, or additional scanner. Relays are also provided for inter-group configuration which can be set on-the-fly and allow for the various modes of operation. 42 can be programmed to the following configurations:
To maximize the SM4000 series versatility, the user can access and control any relay at any time including multiple relays within the same group. |
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Galvanic Isolated ArchitectureThe SM4042 and the SM4022 feature a high voltage galvanic isolation. A high voltage isolation DC/DC power supply and an optically isolated high-speed communication channel form a barrier between the scanner and the PC. The benefit is a floating, guarded switching system, with very low conductive and capacitive noise coupling, as well as a very low leakage to the PC chassis. Ground-loops typically associated with the PC Chassis and power supplies are also eliminated. |
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Isolated RelaysTo further minimize the noise coupling and capacitance, the SM4000 series utilizes isolated and guarded relay contacts and coil drive. Isothermal construction guaranties low thermal EMF offset which is crucial when performing precise resistance, voltage, current, temperature and many other sensitive measurements. Compare this specification with other plug-in relay scanners, which are not specified for thermal EMF, and commonly exhibit offsets higher than a hundred micro volts. |
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Shielded ConstructionShielded construction contributes in several ways. A guard shield reduces RFI/EMI emissions and susceptibility. Combined with the floating architecture, noise coupling into the switching system is greatly reduced. In addition, the covers improve the isothermal properties of the unit, and provides safety to the user by preventing accidental contact with the potentially lethal voltages. |
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On Board IntelligenceThe SM4000 series employs an on-board Microcontroller, allowing the scanner to run autonomously from the PC, and execute complex operations in response to high level commands. In addition to improving product control it also guarantees repeatable switching performance. The user has full control of the scanner and communicates with it using a set of simple high level commands. Even-though the SM4000 series allows the user full control to implement any switchable combination, the Microcontroller's pre-defined operation modes (when set) protect the scanner from inadvertently performing prohibited and potentially damaging commands such as shorting several active inputs together. |
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Scan List OperationWith a pre-stored switching sequence in the on-board Scan List, any channel sequencing at any order can be programmed. The Scan List is also designed to accommodate multiple relay scanners, for high channel count. Up to 192 points can be stored in the scan sequence, which may include channels from multiple scanner modules. The maximum number of channels is limited to 1,000. |
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Trig Scan ModeIn this mode the SM4000 series scanner is slaved to an external device which provides hardware or software trigger causing the SM4000 to step through the Scan List table. Each trigger will advance the scanner to the next point in the table. As with all other scanning operations, Relay's Settling time can be set. |
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In
the 2-Wire configuration, each of the 40 measurement channels of an
SM404x may be routed to the DMM. The DMM is physically connected to
Group A-bus. While in TwoWire configuration, accessing higher channels,
in groups B,C or D, the inter-group relays are automatically engaged
to connect the appropriate group to the A-bus.
While
in the 4-Groups configuration, up to four instruments may be connected
to a single SM404x. Each instrument can access channels within its respective
group. Alternatively, if set to the Universal configuration, each of
the instruments may access any of the 40 channels, as well as have multiple
instruments connected to the same channel at the same time.
In
the 4-Wire configuration, the SM404x can route 20 4-wire channels. The
DMM source pair is connected to the A-bus (for groups A, B access) and
the sense pair is connected to the C-bus (for groups C, D access). For
example, responding to 'Select Channel 2' command, the scanner opens
all closed channel relays, followed by closing of Ch2 and Ch22 relays.
When
combined with the SM2044, the SM404x can provide a 6-Wire guarded measurement
system, by selecting SixWire configuration. Issuing 'Select Channel
2' results in the opening of all closed channel relays, followed by
closing of Ch2, Ch12 and Ch22 relays. This system is limited to 10 channels
of six wire inputs. Additional scanners can expand it up-to 1,000 channels.
Multiple
Scanners can be deployed to form over 1000 channels. The "Tree-Relay"
ensure minimum noise pickup, capacitance and leakage as seen by the
instrument connected to the common bus.
