MHV-4(Data sheet V4.0_02)

4 channel, 800 V
detector bias supply

mesytec MHV-4 is a modern 4-channel high precision bias supply unit for detector bias
voltages up to 800 V. It is designed to supply highly stable bias voltage for all types ofsilicon and gas detectors. The output current is limited to 20 uA.
The new revision allows easy operation of large area avalanche diodes, by compensating
the bias voltage with temperature. Temperature measurement can be performed withminiaturized NTC temperature sensors. The four temperatures are also available via USBor mesytec control bus.
Features:•Precise voltage setting up to 800 V,
in steps of 12.5 mV•

lowest noise voltage of < 1 mVrms at 400 V•

Current display resolution 1 nA•

4 large and bright LED displays allow
simultaneous survey of all currents or voltages•

Full 4 digit display•

Universal 4 channel temperature measurement andHV compensation for avalanche diodes.
(external sensors: standard NTCs)•

Adjustable HV ramp speed•Output connectors: SHV or BNC•

Adjustable current warning threshold and voltage
limit for each channel. Acoustical and opticalcurrent warning•

Individual polarity select for each channel at
the front panel•

Remote control: All parameters can be set
via USB or mesytec control bus(using an MRC-1 / MRCC master module)mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, 85640 Putzbrunn, Germany
phone: +49 - 89 / 456007-30 fax: +49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

MHV-44 channel bias supply

Technical Data
Temperature measurement

Power consumption••••+6 V+700 mA–6 V–70 mA–12V–50 mAdue to low power consumption no cooling fansnecessary

Voltage Output••••••••••••

Voltage range: 0 … ±800 V
adjustable in steps of 12.5 mVHigh quality rotational encoders withdynamic step width
Typical noise N < 1 mV (400 V, 5 Hzto 100 MHz)
Voltage stability: typ 0.015 %/ 0C
Calibration precision: 0.5 %Output current max. 20 uA per channel,limited
Adjustable voltage ramp up and down of 5 V/s
up to 500 V/s
Ramp up after power failureDisplay•••••

Full 4 digit displayCurrent display with 1 nA resolution
up to 20.00 uA
Voltage display:
up to 100 V: 0.01(25)V steps
100 V to 800 V: 0.1 V steps

When using temperatur sensitive detectors likeSi- detectors, which have temperature dependent
leakage currents , or Scintillators with temperaturedependent light output, it is helpful to monitor thedetector temperature to allow later corrections at
the analysis of data.
The new revision of MHV-4 allows to monitor up
to 4 temperatures with unexpensive standard
NTCs, which can be glued to a setup. Measuredtemperatures can be displayed and read out via
USB or mesytec control bus.
The high resistance of the sensors, and low passfilters in the module, allow to use almost any
available cabeling like coax or twisted pair cables.

Sensor connector pinout:

Current warning••

Individual warning thresholds adjustable from
1 nA to 20 uA.
Acoustical and optical warning when thresholdis exceeded.
•Connectors••••

HV outputs: BNC or SHV
USB remote control: standard USB B
mesytec control bus: Standard NIM Lemo
connector 00 series
Temperature sensors: 2.54 mm pitch
header connector

PinSignal

1, 2gnd3, 4Sensor 0, gnd

5, 6Sensor 1, gnd

7, 8Sensor 2, gnd

9, 10Sensor 3, gnd

Sensor type: NTC thermistor, Epcos B57861S502-F40 (5 kΩ @ 25 °C, B = 3988)

mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, 85640 Putzbrunn, Germany
phone: +49 - 89 / 456007-30 fax: +49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

2/9MHV-4

MHV-4 Frontpanel

Bright 4 digit display

Polarity indicator

Digital encoder for allsettings

4 channel bias supply

MHV-4 Backpanel

HV outputs(BNC or SHV)
Sensor inputs for temp.
compensation

mesytec control bus input
USB B connector

Main channel switch,
status indicator

Dip switches for
HV ramp speed anddisplay brightness
Adress coder for mesytec
control busSettings selector switch
and indicators
NIM power connector

Display selector switch
and indicators
RC indicator(panel locked)
Bus indicatormesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, 85640 Putzbrunn, Germany
phone: +49 - 89 / 456007-30 fax: +49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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MHV-44 channel bias supply•

Temperature compensation:
MHV-4 allows automatic compensation of HVlevel according to temperature measured at oneof four possible sensor inputs.

MHV-4 frontpanel operation•

On / Off:push main channel switch to toggle between on
and off status.
On:
HV will be ramped up/down with given HVramp speed (ramp speed is set by backpanel
dip switch or via RC).

Tcomp parameters are accessibe if at least one
sensor is connected.
Three parameters are adjustable:

Red „on“ indicator will blink during ramping
and will light steadily when preset voltage isreached.

Source:select input number 0...3 as sensor source for
the HV output channel.

Display shows measured voltage at HV output.

HV will then be autmatically compensatedaccording to parameters „offset“ and „slope“.

Off:
If HV = 0 V, red „on“ indicator LED turns off.
Display shows preset Voltage instead of measured output voltage.

If „off“, no compensation will be applied tooutput voltage.
Display can be toggled between source number
and measured temperature at this input byclicking the display selector switch.

Press settings selector to reach the different
settings:•Voltage limit:
Voltage limit can be adjusted beetween 0 and800 V. Voltage preset can not be set higher thanvoltage limit.

•Current limit:
If current limit is exceeded, an acoutsical alarm
will be emitted, and channel indicator LED
will blink.
Max. current can be adjusted between
0 and 20 uA.

••

Offset:defines the temperature with a compensation
value of 0 V (no compensation).
Values between 0 °C and 50 °C are possible.

•Slope:defines the (positive or negative) compensation
slope, applied referring to the offset
temperature. Values between –9.99 V/ °C and9.99 V/ °C are possible. A reasonable starting
value for typical APDs will be +0.8 V /°C.

Polarity:
Can be set positive or negative.
If polarity is changed while HV is on, HV will
be ramped down automatically before polarity
is changed. The Voltage will be automatically
set to 0 V.

mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, 85640 Putzbrunn, Germany
phone: +49 - 89 / 456007-30 fax: +49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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MHV-44 channel bias supply

Remote control via USB••••

MHV-4 can be remote controlled via USB, e.g.
using a standard ASCII terminal program.
Baud rate: 9.600 Bd
Data Format: 8N1 (8 bit, no parity, 1 stoppbit),
input characters are echoed

STC c nset temperature compensation forchannel c
n = channel number of NTC
element (0...3, -/4 = off)
e.g.: STC 0 0 switches tempcomp. for channel 0 on andselects NTC input 0 as source for
T information.
STC 0 - switches temp comp.
for channel 0 off.

STO c ttt

set reference temperature
for channel c
ttt = temperature in 0.1 °C
e.g.: STO 0 285 sets reference
temperature for channel 0 to
28.5 °C

STS c ssss

set temperature compensation
slope for channel c to ssss mV/ °C
e.g.: STS 0 800 sets slope forchannel 0 to 0.8 V/ °C
positive / negative values allowed
e.g. STS 0 -1200
for -1.2 V/ °C

SRA n

set HV ramp speed
n = 0: 5 V/s, 1: 25 V/s,2: 100 V/s, 3: 500 V/s

Commands

c = channel number 0...3, 4/a = all
Set Commands

ON cswitch channel n on

OFF cswitch channel n off

SU c vvvv

set voltage of channel nvvvv = voltage in 0.1 Ve.g.: SU 0 4000 sets channel 0 to400V

SUL c vvvv

set voltage limit of channel nvvvv = voltage in 0.1 Ve.g.: SUL 0 4000 sets voltage
limit for channel 0 to 400 V

SIL c iiiii

set current limit of channel niiiii = current in nAe.g.: SIL 0 4000 sets currentlimit channel 0 to 400 V

SP c pAS c nset polarity of channel np = polarity: p/+/1 or n/-/0e.g.: SP 0 n sets polarity channel
0 to negative
For security reasons: if HV is on,
it will be switched off automati
cally, HV preset will be set to 0 V,
polarity is switched when
HV is down.
After switching:set presets again to desired values.
enable (n=1)/disable (n=0) auto
shutdown of channel cRead Commands

RU cread voltage channel c

RUP c read voltage preset channel c
RUL c read voltage limit channel c
RI cread current channel c

RIL cread current limit channel cRP cread polarity channel c

RTC c read complete settings for temp
compensation channel c
RT cread temperature at input c

RRAread HV ramp speed

mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, 85640 Putzbrunn, Germany
phone: +49 - 89 / 456007-30 fax: +49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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MHV-44 channel bias supply

Remote Control via mesytec serial event bus(MRC-1 / MRCC master controller needed)
As an option, MHV-4 can also be remotely controlled via mesytec control bus using the rc master modules MRC-1 or MRCC.

MRC-1 / MRCC command Summary
cmd format:
cmd bus [dev] [adr] [val]This enables setting up larger systems, also combining different modules (such as MHV-4 and the 16
channel shapers STM-16 / MSCF-16 or theneutron/gamma discriminator MPD-4 / MPD-8),
all being accessed from one command interface.
The setup data for all connected modules can be
stored in the MRC-1 / MRCC. After power up orwhen the reset pushbutton is pressed, it automatically reinitializes all devices with the stored values.

busdevadrvalMemory layout

ON bus dev
Activates remote control for given device @ bus.
Will invoke rc settings instead of panel settings.
(Be sure to have parameters set correctly or in a surerange before activating rc.)

All MHV-4 parameters that are accessible by remotecontrol are represented in a memory page that can beread and/or written by MRC-1 / MRCC commands.
Write registers contain setup/preset values and canbe written/read. The corresponding read (only) registers represent the measured values. They may differ
from the preset values (e.g. when a channel voltage
is preset, but the channel is switched off).
Layout of the memory page is described on the following pages.
Read/Write access

Memory positions are written with the SE (= set)command and read with the RE (= read) command.
(please see command listing below for detailed cmdinformation)
Mirror page

For very safe operation a mirror page is available. It
is a second write memory page that can be written
without triggering changes in the current MHV-4 setup. Write and read commands are SM (= set mirrorvalue) and RM (= read mirror value). When everything is written and confirmed, values can be all together copied to the active page with CP (= copymirror page), where they take effect immediately.
The ON / OFF commands lock / unlock the MHV-4
front panel. Lock status is saved immediately andrestored on power up.
Identification code for MHV-4 (detected when running the scan bus command "SC") is IDC = 27

= bus number [0...1]= device number [0…15]= parameter number [0…31]= See memory list page 4

SC busScans given bus (0, 1) and returns id code (IDC) for
each device number that responds. MHV-4 will
return IDC=17.

OFF bus dev
Switches off remote control for given device @ bus.
Returns settings to panel values.
SE bus dev adr val
Set direct memory address adr in device @ bus tovalue val. Changes will take effect immediately if rc
is switched on. For a special safe setup and common
application of all set values, please use the mirror
memory and copy command.
RE bus dev adr
Read value from direct memory address adr
in device @ bus.
SM bus dev adr val
Same as SE command, but writes to the mirror memory page. Values are copied to direct memory
using the CP copy command. Presets can be changed
safely and will only take effect if copied to directmemory.
RM bus dev adr
Read mirror memory – returns the preset value outof mirror memory.
CP bus dev
Copy mirror memory to active memory.
Presets will take effect immediately if rc
is switched on.

mesytec GmbH & Co. KGWernher-von-Braun-Str. 1, 85640 Putzbrunn, Germany
phone: +49 - 89 / 456007-30 fax: +49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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MHV-4

WriteAddressValue••••

ReadAddress

4 channel bias supply

Comment

Write addresses can be read and written.
Read on write addresses delivers written value (possibly corrected by boundary check).
Read addresses are „read only“ and deliver current hardware status which might deviate
from written value.
(due to on/off switches, set limits, transient status, compensation, …)

Voltage 0032

Set / read channel voltage

Voltage 1133

Voltage 2234

Voltage 3335

On/Off 0436

On/Off 1

537

On/Off 2

638

On/Off 3

739

Cur. Lim. 0840

Cur. Lim. 1

941

Cur. Lim. 2

1042

Cur. Lim. 31143

RC on/off (PanelLock)-44

Set by „ON b a“ command, read: 0 = off, 1 = on

Polarity 0

1446

Set / read channel polarity

Polarity 1

1547

Polarity 2

1648

Polarity 3

1749

Current 0-50

Current 1-51

Current 2-52

Current 3-53

Volt. Lim. 0

1822

Volt. Lim. 11923

Volt. Lim. 2

2024

Volt. Lim. 3

2125

Write: 0... 8000 = 0 … 800.0 V
Read: 0 … (-)8000 = 0 … (-) 800.0 V(also indicating polarity)

Set / read channel switch status
Read / Write: 0 = off, 1 = on

Set / read current limit
Read / Write: 0 … 20.000 = 0 … 20.000 nA (0 … 20 uA)

Read / Write: 0 = negative, 1 = positive
Switching polarity automatically includes: channel switched off, voltage preset = 0 for security reasons. Switching may take time depending on HV ramp speed.

Read channel current
Read: 0 … (-)20.000 nA

Set / read channel voltage limit
Read / Write: 0... 8000 = 0 … 800.0 V (no polarity)mesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, 85640 Putzbrunn, Germany
phone: +49 - 89 / 456007-30 fax: +49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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MHV-4

Write
Address

Value

ReadAddress

4 channel bias supply

Comment

Temperature 0-26

Temperature 1-

27

Temperature 2-

28

Temperature 3-

29

Read: 0 … 500 = 0 … 50.0 °C(999 if no sensor connected)

T Comp. Slope 0

64

100

Read / set slope for temperature compensation

T Comp. Slope 1

65

101

T Comp. Slope 266102

T Comp. Slope 367

103

T Comp. Offs. 068

104

T Comp. Offs. 1

69

105

T Comp. Offs. 270

106

T Comp. Offs. 3

71

107

T Comp. Src. 072

108

T Comp. Src. 173

109

T Comp. Src. 274

110

T Comp. Src. 375

111

HV prec. 076

112

HV prec. 177

113

HV prec. 278

114

HV prec. 379

115

Ramp Speed

80116

Read temperature at sensor (if connected)

Read / write: 0 … 19.999 = –9.999 V/ °C…+ 9.999V /°C(10.000 = 0 V /°C)

Read / set offset(= Temperature with compensation = 0.0 V)
for temperature compensation
Read / write: 0 … 500 = 0.0 °C … 50.0 °C

Read / set sensor input for temperature compensation.
Read / write: 0...3 = input #, 4 = off

Read / set voltage in binary units, 1 = 12.5 mV
Read / write: 0 … 64.000 = 0.0 … 800.0 V

Read / set HV ramp speed
Read / write: 0 … 3
0 = 5 V /s, 1 = 25 V /s, 2 = 100 V /s, 3 = 500 V /smesytec GmbH & Co. KG
Wernher-von-Braun-Str. 1, 85640 Putzbrunn, Germany
phone: +49 - 89 / 456007-30 fax: +49 - 89 / 456007-39
info@mesytec.com - www.mesytec.com

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