RAZORBILL MP240 Page 5 User Manual Download

Page: 5 / 40

Version 1.1 (released 14 April 2021)

http://razorbillinstruments.com

Page 5 of 40

Size

Length

180 mm

Width

185 mm

Height

65 mm

Weight

approx. 1.2kg

Power supply

USB operation

5 V, 200 mA

Digital Input Port

5V, 100 mA

Switched Signal

Max voltage

30 V

Recommended current

< 10 mA

Max switching current

400 mA

Max carrying current

1000 mA

Switching behaviour

order

Break before make, 3 ms typ.

topology

Double pole quad throw, or as
independent relays (USB control
only)

Unconnected outputs are
grounded

Max switching speed

5 s

-1

Switching cycles

> 10

at maximum current

> 10

at recommended current

Isolation

Typical use case

<2 aF

Connectors

Switched signals

BNC

USB

USB-B

Digital input

D Sub 15

Ground

4mm plug, fork, or bare wire

Materials

Enclosure

Powder coated aluminium

Front and rear panels

Printed aluminium

See also: Electrical specifications of the digital input port on
page 20

The multiplexer must not be switched when the max switching current is

exceeded

When the multiplexer is used with an AH2550 capacitance bridge to

measure a capacitance of 1 pF, changing the adjacent channel from <10aF to
100nF causes a spurious change of less than (0.3+2i)aF on the 1pF
measurement.

Summary of Contents for MP240

Page 1: ... impedance measurement systems This multiplexer can be used in conjunction with other Razorbill Instruments products it is ideal for use with devices such as the UC200 that contain more than one capacitive sensor or in cases where more than one stress or strain cell is used simultaneously The MP240 may be controlled by USB or by a digital input The digital input is compatible with Andeen Hagerling...

Page 2: ... some basic understanding of the conventions regarding the use of sensitive laboratory equipment is assumed This document is designed to allow the end users to safely and efficiently set up and operate the MP240 High Isolation Multiplexer and use it in conjunction with other Razorbill Instruments products The document is also designed to draw attention to any risks and hazards involved in operatin...

Page 3: ...ty USA 8 Disposing of your MP240 9 Suitable Operating Environments 10 Operating Modes 10 Getting Started 11 Reading the Front Panel 11 Back Panel Layout 13 Typical First Time Set up 14 Technical Discription 15 Grounding Notes 15 USB Serial communication 17 Microsoft Windows 17 Linux Mac OS and other systems 18 Using the digital input port 18 Pin allocations 19 Enable pins 19 Power supply pin 19 El...

Page 4: ... 40 MP240 HIGH ISOLATION MULTIPLEXER SCPI core commands 23 SYSTem commands 31 ROUTe commands 32 MODE commands 35 Example Code Snippet 37 Caring for your MP240 Multiplexer 38 Installing a Firmware Upgrade 38 Cleaning 38 Firmware licencing information 38 SCPI PARSER 39 LUFA 40 ...

Page 5: ...outputs are grounded Max switching speed 5 s 1 Switching cycles 106 at maximum current 108 at recommended current Isolation Typical use case2 2 aF Connectors Switched signals BNC USB USB B Digital input D Sub 15 Ground 4mm plug fork or bare wire Materials Enclosure Powder coated aluminium Front and rear panels Printed aluminium See also Electrical specifications of the digital input port on page 2...

Page 6: ...td Manufacturer s Address Unit 8 Castlebrae Business centre 40 Peffer Place Edinburgh EH16 4BB CE Mark The manufacturer hereby declares that the product Product Name High Isolation Multiplexer Model Number MP240 has been tested to the following standards EN61326 1 2013 and complies with the following European directives 2014 30 EU EMC Directive Dr Alex Ward Managing Director ...

Page 7: ...turer s Address Unit 8 Castlebrae Business centre 40 Peffer Place Edinburgh EH16 4BB UKCA Mark The manufacturer hereby declares that the product Product Name High Isolation Multiplexer Model Number MP240 has been tested to the following standards BS61326 1 2013 and complies with the following UK legislation Electromagnetic Compatibility Regulations 2016 Dr Alex Ward Managing Director ...

Page 8: ...uirements of FCC Rule Part 18 RESPONSIBLE PARTY located in the United States Testing Partners LLC 18200 SR 306 Chagrin Falls OH 44023 info testingpartners com The responsible party warrants that each unit of equipment marketed under this Declaration of Conformity will be identical to the unit tested and found acceptable with the standards and that the records maintained by the responsible party co...

Page 9: ... UK Razorbill Instruments will be happy to arrange for this product to be picked up and disposed of properly at the end of this products life This is providing that the product has not been disassembled or contaminated This is part of Razorbills commitment to the Waste Electrical and Electronic Equipment WEEE Directive of the European Community and the corresponding national laws For products outs...

Page 10: ...put port if available or from USB if not Control signals from the digital input port are ignored The high and low relay banks can be independently controlled in this mode Digital Input Only The multiplexer will be in this mode if a digital input cable is connected but USB is not The multiplexer functionality is directly controlled from the input port The microcontroller does not run and the front ...

Page 11: ...ly in this mode GETTING STARTED Reading the Front Panel Figure 1 The front panel of the MP240 As the primary mode of control of the multiplexer is using serial commands over a USB connection the front panel does not feature any input controls and provides only limited information via 6 LED indicators High relay bank switched terminals Low relay bank switched terminals High relay bank common termin...

Page 12: ... BNC terminal is the common connection for the high side relay bank It can be connected internally to terminals H1 to H4 This terminal would typically be connected to the output terminal of your measurement device such as an LCR or Capacitance Bridge The terminal on the measurement deice is typically labelled high force or excite Lcom Terminal This BNC terminal is the common connection for the low...

Page 13: ...ayout USB Port A type B USB port To use the Multiplexer in USB mode or digital input mode with USB monitoring connect a USB cable from the PC to this port If you wish to use the multiplexer in digital input mode only leave the USB port empty If a USB cable is connected the multiplexer acts as a bus powered USB2 0 Full Speed device Digital Input Port This 15 pin D Sub connecter can be used to contr...

Page 14: ...ipment to the BNC jacks Hcom and Lcom Connect the first device you wish to measure to H1 and L1 connect the next device to H2 and L2 etc Connect the MP240 using the supplied USB cable3 by plugging into the rear panel USB port and any available USB port on the PC Install the correct drivers onto an available computer terminal to be used as the control PC The drivers are available on the Razorbill I...

Page 15: ...y banks these are intended simultaneously switch the high and low measurement arms of a capacitance bridge LCR or similar measurement instrument Each of these relay banks consists of four BNC connectors that can be either grounded or connected to the COM terminal in the corresponding bank The layout is illustrated in Figure 3 Grounding Notes The analogue grounds for the High and Low relay banks ar...

Page 16: ... derived from the shield of the connected cables in each bank Figure 3 block diagram The case ground is connected to the USB ground and digital input port ground It is recommended to attach the case ground to a clean ground This is particularly important if the multiplexer is 4 The device was tested for FCC CE and UKCA compliance with the jumpers in place It is not guaranteed to be compliant witho...

Page 17: ...g 5 m of cable Microsoft Windows Razorbill instruments supports the MP240 on Microsoft Windows 7 and higher Before using your multiplexer you should install the necessary drivers for your operating system these are available on the Razorbill Instruments website The Multiplexer may work with windows built in drivers but our drivers have several advantages including improved reliability of the USB l...

Page 18: ...her than Microsoft Windows Using the digital input port The Digital input port is designed to be compatible with the sample switch output of Andeen Hagerling capacitance bridges It can also be used to control the multiplexer from any logic source between 3 V and 25 V If power is provided to the multiplexer through the digital input port this will be used to drive the relays in preference to power ...

Page 19: ...4 NC 15 NC Shell Ground Enable pins The enable pins are active high When a channel enable pin is driven high the relevant relays in both the high and low bank will be set to connect the corresponding BNC connector to the COM BNC connector When a channel enable pin is pulled low or left floating the corresponding BNC connectors will be connected to ground Power supply pin Pin 6 is intended for use ...

Page 20: ...ional voltage regulation are provided but there remains some potential for excessive noise on this pin to affect the signal path Warning A voltage between 0 2 V and 3 8 V applied to pin 6 when USB power is also connected may damage the multiplexer Confirm the voltage of the power supply is correct and has sufficient current available to prevent voltage sag Electrical ratings Channel Enable Pins Ab...

Page 21: ...actual command may use upper or lower case e g the keyword OUTPut means that the commands OUTP OUTPUT output and outp can be used and have the same meaning The section enclosed in square brackets is optional The channel to operate on which may be 1 to 4 inclusive n A terminator When sending commands to the instrument CR LF or CRLF may be used Responses from the instrument will always end with CRLF...

Page 22: ...e complete chain including terminator is no longer than 255 characters Otherwise the input buffer will overflow and some of the commands will be lost A command which is not recognised by the instrument is followed by a parameter of the wrong type or otherwise can t be understood by the instrument will generate an error Errors are stored in a queue first in first out and as long as there is somethi...

Page 23: ...SYSTem ERRor NEXT Get last error 31 SYSTem ERRor COUNt Get number of errors 32 ROUTe SELEct Set an exclusive route 33 ROUTe SELEct Check if a route is set 33 ROUTe bank Set an individual relay 34 ROUTe bank Get the state of an individual relay 34 MODE EXT Set serial monitoring mode 35 MODE EXT Check if the device is in serial monitoring mode 35 MODE PWRSource Check if the relays are using external...

Page 24: ...Clears all status data structures in the device including all status registers and the error queue Example CLS ESE ESE No response int Description Set or query the Standard Event Status Enable register This command is required for SCPI compatibility and is only minimally supported Refer to the SCPI standard for more information Example ESE ...

Page 25: ...ents com Page 25 of 40 MP240 HIGH ISOLATION MULTIPLEXER ESR int Description Query the Standard Event Status Register This command is required for SCPI compatibility and is only minimally supported Refer to the SCPI standard for more information Example ESR ...

Page 26: ...umber e g 1 0 0 Description Query the device identity information The response is four strings separated by commas Almost every SCPI like instrument supports this command so it can be used by software to identify the instrument The firmware number uses the major minor release format Changes to the release version are small bugfixes or changes in packaging and distribution Changes to the minor vers...

Page 27: ...he SCPI standard but has no effect as the flag is always set The query form queries the operation complete flag and will always return 1 Example OPC RST No Response Description On receipt of this command the device resets to power on settings All relays are set to ground and the device operating mode returns to USB Only All status registers and the error queue are cleared The USB serial connection...

Page 28: ... MP240 HIGH ISOLATION MULTIPLEXER SRE SRE No Response bool Description Set or query the service request enable flag This command is required for SCPI compliance but even with service requests enabled the multiplexer will never raise them So this command has no effect Example SRE ...

Page 29: ... is an integer it represents 8 individual bits flags Only bit 2 is used in the multiplexer and indicates an error is in the error queue In general it is easier to use SYST ERR COUNT To check for errors but this command is provided for compatibility with the SCPI standard Example STB TST bool Description On receipt of this command the device resets and executes an internal self test The response wi...

Page 30: ...Page 30 of 40 MP240 HIGH ISOLATION MULTIPLEXER WAI No Response Description Wait for the current operation to complete This command is required for SCPI compliance but all there are no commands which take time to execute so the instrument will never wait Example WAI ...

Page 31: ...eue the error LED on the front panel will be lit Note that in some cases one malformed command can generate several errors SYSTem ERRor NEXT int string Parameter int A numerical error code For a complete list of codes and their meanings refer to the SCPI standard Parameter string A short human readable description of the error Description Retrieves the error from the top off the error queue As the...

Page 32: ...mple SYST ERR COUNT ROUTe commands the route commands are used to set routes through the multiplexer Select is exclusive and will configure all relays so that only the specified route is set More advanced configurations are available the via H and L commands All ROUTe commands have corresponding query forms ROUTe commands are unavailable when the device is in monitoring mode as in this mode the re...

Page 33: ...on 0 to 4 Description The command exclusively sets a route in both high and low relay banks Any other relays that were previously enabled are disabled If called on channel 0 all relays are disabled The query form returns 0 if no relays are enabled 1 to 4 if a route is exclusively set 1 if more than one route is set and 2 if the high and low relay banks are differently configured Example SELE 1 ...

Page 34: ...BNC connector marked COM 0 means the specified front panel BNC connector will be grounded Parameter bank H or L corresponding the high and low relay banks Description This command allows relays to be individual set while the query form allows their state to be checked Unlike SELEct this command is not exclusive so has no effect on other relays The channel number in this case must be between 1 and ...

Page 35: ...XT can be used to hand over control to the digital input port MODE EXT bool MODE EXT No response bool Parameter bool 1 means the device will be controlled from the digital input port 0 means that the device will be controlled from the USB connection Description This command puts the device in serial monitoring mode In this mode the USB connection can be used to monitor the state of the relays but ...

Page 36: ...nput port to control the relays 0 means power is being derived from USB Description This query allows the user to check which power source is being used to operate the relays It cannot be set over the USB serial bus so there is no command form Power from the digital input port is always used for the relays if it is present The microcontroller always runs on power derived from USB Example MODE PWRS...

Page 37: ...mple of how you might achieve that in Python requires PySerial to be installed import serial import time with serial Serial COM1 as mp240 mp240 write b SELECT 1 n time sleep 1 take a measurement here mp240 write b SELECT 2 n time sleep 1 take a measurement here mp240 write b SELECT 0 n The comments should be replaced with code that takes a measurement from the capacitance bridge or other multiplex...

Page 38: ...C or you can check the Razorbill Instruments website Cleaning The multiplexer may be cleaned with a cloth dampened with warm soapy water or mild solvents like isopropanol Avoid using abrasive cleaners or using large quantities of liquid which could enter the multiplexer and cause damage FIRMWARE LICENCING INFORMATION The firmware uses two open source components scpi parser and LUFA The software li...

Page 39: ... in the documentation and or other materials provided with the distribution THIS SOFTWARE IS PROVIDED BY THE AUTHORS AS IS AND ANY EXPRESS OR IMPLIED WARRANTIES INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED IN NO EVENT SHALL THE AUTHORS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT INDIRECT INCIDENTAL SPECIAL EXEMPLARY OR CONS...

Page 40: ...n notice and warranty disclaimer appear in supporting documentation and that the name of the author not be used in advertising or publicity pertaining to distribution of the software without specific written prior permission The authors disclaim all warranties with regard to this software including all implied warranties of merchantability and fitness In no event shall the author be liable for any...

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