FB supply photo

Fastbus Power Supplies

HGB, 03/18/1996, rev. 01/28/97

Overview

  1. Function
  2. Technical Data
  3. Connectors
  4. How to hook up the supply to the Fastbus crate
  5. Power on procedure
  6. Power off procedure
  7. Peformance Test Results
  8. Further Documentation
Each of the four Fastbus crates of the SuperK OD DAQ system is supplied with regulated and stabilized DC voltages by a separate power supply unit. The supply units are refurbished surplus units formerly built for SLAC, Palo Alto, CA, and provide +5V, -5.2V, -2V, +15V, and -15V DC from a single-phase 120V AC input.

Due to extensive use of ECL technology for achieving 1/2 nanosecond or faster digital logic transfers the power requirement for Fastbus electronic cards can be very high.
For example, for a set of five LeCroy 1877 TDC modules and one BiRa FSCC controller the typical power consumption is approx. 40A at +5V, 30A at -5.2V, 15A at -2V, and approx. 1A at +/-15V.
Thus, the power supplies have to be very sturdy and also well cooled!

power lines The units come in two designs, both with a 31" tall, 9.5" wide black front panel (half of the standard electronics rack width) and a chassis of about 27" deep:
model MK II type 1 (SLAC # 135-970) and model MK II type 2 (SLAC # 135-986).

The differences between the two designs are a) in the way they will be mounted into an electronics rack. For SLAC, two power supplies could be mounted next to each other vertically in the 19" wide rack space. The 'type 1' model is mounted on the left hand-side and 'type 2' on the right hand-side of the rack. For SuperK only one Fastbus crate and one power supply unit is mounted in one rack. [So, half of a 31" tall side of the electronics rack is unused - good for plenty of cooling.]

The second difference is that the type 1 models are stuffed with 150A switching supplies for the +5V and -5.2V outputs (NJE750 types), and the type 2 models with 50A/70A switching supplies of these outputs (Kepco RMX 05 types). Due to lack of availability of a 3-phase 208/120 VAC system in the SuperK tank the original SLAC units had to be rearranged to be able to run with single-phase 120 VAC only. Also, the limited number of identical SLAC units transferred to the U.Wa. forced us to have the units prepared for SuperK with two different output capabilities. Still, both designs have been tested more than sufficiently that they are working perfectly within the power requirements for the SuperK Fastbus electronics.

Function

 The power supply unit contains of 7 function blocks (also as postscript file available):

FB supply block diagram

Each of the 5 output voltages is generated by a separate switching power supply (= 5 function blocks). The 150A supplies each have their own built-in cooling fans, and the lower-current supplies are sufficiently cooled by large heat sink areas at their cases.

A multi-conductor cable with feedback voltages from the Fastbus is used to regulate each voltage to a highly stable level.
An optional voltage and current monitor can be connected as well.

Secondly, there's a line filter for the 120 Volt AC input and control block, operated by a relay interlock system, with Reset and ON and OFF push-button switches.

Technical data
Inputs:
  • AC 100 ... 120 V, single-phase 50-60 Hz, approx. 3 kVA max.
  • 4 Interlock signals from switches, e.g. temp. thermostat, etc.
  • 2 Interlock signals from digital TTL-level sources
Outputs:
  • AC 100 ... 120 V (after CTRL PWR switch), for fans, accessories, etc.
  • DC +5.0 V, 150 A max. (type 1) / 50-70 A max. (type 2)
  • DC -5.2 V, 150 A max. (type 1) / 50-70 A max. (type 2)
  • DC -2.0 V, 150 A max.
  • DC +15 V, 2.5 A max.
  • DC -15 V, 2.5 A max.

Connectors

How to hook up the supply to the Fastbus crate

 See also the illustrations of the rear crate side.

  1. Use 1/0 or 2/0 AWG cables for the high-current voltages +5V, -5.2V and -2V and their returns. Mount them with 1/4" ... 5/8" screws to the adjacent (labeled) terminals, with one end to the 1/2" copper terminals of the supply unit and the other end to the Fastbus crate terminals on the crate's rear side.

  2. Use 16-20 AWG cables for the +/-15V and Return voltages, by connecting the cables directly at the switching supply boxes (position PS4 = +15V, and PS5 = -15V, both at the rear side of the supply) and then to the crate's 15V terminals on the rear left hand-side.

  3. The +/-28V terminals of the crate are unused for SuperK operations.

  4. Connect the "Remote Sense" cable with the Molex connector to the J1 jack at the lower rear panel of the supply unit and with the 30-pin header connector to one of the free rear backplane 130-pin slot headers (preferred one of the 2 center headers).

    Pin 1 of the 30-pin connector must match with the A1 pin of the Fastbus slot header in order to have the correct voltages returning to the power supply unit!!

  5. Use the AC outlet (female) stub for an external fan tray or additional accessories which should be switched on simultaneously with the CNTRL PWR ON switch.

  6. Plug the AC power cord (male 3-prong) to a standard 120V AC outlet with 15A or higher current capability (i.e. 1800 VA).

Power on procedure
  1. Before first power on - after installation or replacement - check if all connections are correct and unplug ALL electronic modules in the Fastbus crate.

    A reversed 150A output or missing remote sense connection can destroy k-Dollars worth of electronics equipment (including the power supply) in a fraction of a second!!

  2. Turn the CNTRL PWR ON switch to ON position.
    Now the red CNTRL PWR ON LED should be on and the external AC accessories (Fastbus fan tray) should start working.

  3. Push the RESET button.
    Now all six yellow Interlock LEDs should be on. If not, that indicates that one of the interlock sensors indicates that something is wrong.
    [Actually, for SuperK none of the interlock inputs is used. Thus, the interlock section is completely disabled and all yellow LEDs will show valid states anyway.]

  4. Push the ON button.
    Now the red P.S.ON LED should be on and the unit's main power is on and happily supplying the DC voltages to the Fastbus crate. All 5 voltage indicator LEDs (green) below the voltmeter should be on as well!

  5. With the current Fastbus setup for SuperK - one BiRa FSCC controller (with RS485 Interface card), five LeCroy 1877 TDCs, one Struck Latch, a set of Reduced Term./ANC. cards, and the custom-made Interface - the ampere panel meter should show approximately:
    • 30 Amp. at -5.2 V,
    • 40 Amp. at +5 V,
    • 15 Amp. at -2V.

Caution !

If after turning on the main power one or several of the green voltage indicator LEDs are NOT on, then the supply unit should be switched off immediately to avoid damage to the Fastbus electronics!!
Check if the REMOTE SENS line is inserted correctly! Also, possibly one of the AC fuses of the individual switching supplies might be blown and needs to be replaced.
If none of the above helps to get the unit fully functioning again, then replace the whole supply unit with the spare one. And call for service as well ([0-001010]-1-206-685-4725 or [0-001010]-1-206-713-5919 or email to berns@phys.washington.edu)!

Power off procedure
  1. Push the OFF button.

  2. In case the Fastbus modules are heated after a long run, let the fan tray run for a few more minutes to help cooling down.
    Then finally, turn the CNTRL PWR ON switch to OFF position.

Performance Test Results

Further Documentation

HGB, last edited 01/28/96.