[Halld-cal] Fwd: Re: Power supplies and relays for monitoring. Corrected.

[Elton Smith]

-------- Original Message --------
Subject: 	Re: Power supplies and relays for monitoring. Corrected.
Date: 	Fri, 09 Nov 2012 11:50:24 +0200
From: 	Georgios Voulgaris <gboulgaris at phys.uoa.gr>
Reply-To: 	gboulgaris at phys.uoa.gr
Organization: 	University of Athens
To: 	Elton Smith <elton at jlab.org>



Hi Elton,
     I checked the design as realized and is using 4 trigger lines not 1 
trigger and 2 select. So I corrected some numbers in paragraph 4 but the 
scenario is the same. Please ignore the previous mail.

George.

 1.      I checked the specifications for the MPOD 8008L. It is
    programmable 0 to 8 V with 12 bit accuracy that is 2 mV. This is
    very good. So its easy to scan the voltage range.
 2.      In order to pulse different chains of leds its easy and cheap
    to switch on - off this voltage because its DC. The relay boards are
    cheap but they are slow devices (in the millisecond range) and they
    need another external interface like I2C etc.
 3.      On the other hand if the Lab stocks programmable output modules
    it is more elegant to use them. They are addressable directly
    through the VME and they are fast , microsecond response time. The
    outputs are pulsed  according to the bit pattern loaded on the unit.
    So we don't need an external pulser and all operations are
    completely synchronized by the data acquisition.
 4.      We need 4 triggers (pulse signals) per wedge total signals.  
    In order to reduce the number of signals we can send the same
    signals to a group of wedges in parallel ( on a bus cable). I
    assume  that 8 wedges per group is a reasonable number, so we need
    52 outputs.  The trigger pulse  is regenerated on the wedge board so
    the shape is not affected. Bigger groups are possible depending on
    the fan-out ability of the modules. I think that timing issues in
    the data acquisition should be examined too . Its possible to use a
    single bus per side of bcal, if we introduce termination and
    regeneration boards along the bus.
 5. So the preferable scenario is VME programmable output modules plus
    one or more bus cables.

Bye,
George.



στις 7/11/2012 3:33 μμ, O/H Elton Smith έγραψε:
> Hi George,
>
> Sorry we could not hear you yesterday during the meeting (was your 
> microphone turned on?).
>
> Thanks for these comments. They will be useful in confirming our 
> requirements. The present thought is to use the same supplies that we 
> use for the SiPM bias and power. (Wiener MPOD 8008L and ISEG EHS F 205 
> PF). You could double check the specifications, but I think they 
> should be ok since they satisfy the requirements for the SiPMs. There 
> are 8 outputs per module.
>
> Thanks, Elton.
> Elton Smith
> Jefferson Lab MS 12H5
> 12000 Jefferson Ave
> Postal Suite #16
> Newport News, VA 23606
> (757) 269-7625
> (757) 269-6331 fax
> On 11/7/12 6:07 AM, Georgios Voulgaris wrote:
>> Hi Elton,
>>     I have some suggestions about the PS for biasing the LEDs. What 
>> we need are precision programmable supplies.
>> i) quantity : 2 (one per side) Most 2 per side if this improves the 
>> flexibility.
>> ii) Power : the required power is very small. The common PS type of 
>> 60 W is acceptable.
>> iii) Interface : All programmable PS come with serial and USB 
>> interface some include LAN.
>> iv) Distribution and switching of voltages. I suggest to use 
>> programmable relay boards .
>>      The accuracy of the voltage setting is important. Recently I 
>> bought a supply from Thurlby-Thundar, with setting accuracy of 10 mV 
>> for 650 Euro. This PS has serial, USB, LAN interface and can be rack 
>> mounted. I consider this accuracy adequate for the monitoring. On the 
>> other hand one can buy PS with 1mV setting  accuracy from brand names 
>> like Agilent or Tektronics and other at a price range from 900 to 
>> 1200 Euro. These prices are retail prices but I suppose that JLAB is 
>> getting discounts of 20-30%.
>>     All these devices come with driver for integration in Slow 
>> Controls software.
>> The link for TTi is: TTi <http://www.tti-test.com/>
>>      Programmable Relay boards are cheap.  I haven't use any of them 
>> lately so I dont;t have a suggestion. I include couple of links so as 
>> to get an idea.
>> http://www.ereshop.com/shop/ei2c9ai-p-605.html?gclid=CIOMiJW2vLMCFUW_zAodSDQAEg
>> http://www.apogeekits.com/usb_relay_control_board.htm
>> During the last meeting  I had a good sound reception but my voice 
>> was not getting through! So my comment was not heard!
>> Bye,
>>
>> George.
>

-- 
George Voulgaris, Nuclear & Particle Physics Sector,University of Athens 
Tel: (30)2107276949 Fax: (30) 2107276949 Mobile: (30)6944692936 Home: 
(30)2106516713



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