High Voltage Control

CAEN Model SY527 High Voltage System

The System is organized into "crates"; each crate is a 19" wide, 8U high euro-mechanics rack. The modules bearing the output channels (Channel Boards) consist of 6U plug-in modules Up to 10 Channel Boards may be plugged into a single crate. Different plug-in modules are available (Positive, Negative, Floating and Distributor Boards) and can be freely mixed in a single System in order to obtain the necessary configuration.

Each crate may be controlled locally or remotely. Local control is performed manually through a key-pad and an LCD display located on the Front Panel. Remote control is actuated by means of a video terminal (ANSI VT100 or compatible) plugged into an RS232C connector, which is also located on the Front Panel. In this case, a sophisticated Software User Interface is available, featuring symbolic names for channels, custom status displays and other features designed to help the management of a large number of channels.

Each crate houses a HIGH SPEED (H. S.) CAENET node for the remote control; it allows the possibility of linking one or more crates to a H. S. CAENET controller that acts as a System Control Unit. Available controllers are

   A303 H. S. CAENET IBMTM/PC Controller;
   C117B H. S. CAENET CAMAC Controller;
   V288 H. S. CAENET VME Controller. 

Alarms: On TRIP, OVERVOLTAGE, UNDERVOLTAGE, OVERTEMP., FAN FAILURE, and POWER FAILURE.

Restart at Power-On: Automatic after Power-On or Reset Password protection: On each channel or group of channels CHANNEL PARAMETERS Several parameters are associated with each channel. They depend upon the Board type and can be programmed and monitored in different ways:

   via Local control by using the LCD display and the Keypad;
   via Remote control through the H. S. CAENET link or through the RS232C Port;
   via the Front Panel input signals. 

The following is a brief description of the meaning of all parameters.

   CHANNEL NUMBER (Ch#)
   It is the physical name of the channel (0.00, 0.01 and so on) and is determined by the channel position;
   this parameter is read out by the software and is always associated to the channels monitored both in Local and Remote control.

   CHANNEL NAME (Channel)
   It is the symbolic name of the channel, it can be modified via Remote Control;
   it may be up to 11 characters long and may contain any of the following characters:
   "0..9", "A..Z", "a..z", "#", "&", "%", "$", "*", "_" and "-".
   Via Local Control it is displayed but it is not possible to modify it. 

   VMAX HARDWARE (HVmax)
   It is a hardware Voltage limit; usually it is fixed through a potentiometer.

   VMAX SOFTWARE (SVmax)
   It is the maximum Voltage value (in absolute value) programmable for the channel.
   It can be programmed either via Local or Remote Control.

   V0SET (V0set)
   It is the first of the two allowed Voltage programmable values (in absolute value).
   It is active when VSEL is FALSE. It can be programmed either via Local or Remote Control.

   I0SET (I0set)
   It is the first of the two allowed Current Limit programmable values (in absolute value).
   It is active when ISEL is FALSE. It can be programmed either via Local or Remote Control.

   V1SET (V1set)
   It is the second of the two allowed Voltage programmable values (in absolute value).
   It is active when VSEL is TRUE. It can be programmed either via Local or Remote Control.

   I1SET (I1set)
   It is the second of the two allowed Current Limit programmable values (in absolute value).
   It is active when ISEL is TRUE. It can be programmed either via Local or Remote Control.

   RAMP-UP (Rup)
   Maximum Voltage programmable increase rate expressed in Volt/second (in absolute value).
   When a channel is switched On, or when it is switched from a lower Voltage value to a higher one, 
   the Voltage output drifts from one value to the other at the rate expressed by the Ramp-Up parameter. 
   It can be programmed either via Local or Remote Control.

   RAMP-DOWN (Rdwn)
   Maximum Voltage programmable decrease rate expressed in Volt/second (in absolute value).
   When a channel is switched Off, or when is switched from a higher Voltage value to a lower one, 
   the Voltage output drifts from one value to the other at the rate expressed by the Ramp-down parameter.

   The output voltage of a channel drops to zero following the Ramp-down parameter in these cases:
   When the channel is switched Off (Power Parameter = Off); 
   When the channel has tripped with 0< Trip parameter < 1000; 
   When the channels' outputs are disabled   via the "CH OUT EN" switch. 
   It can be programmed either via Local or Remote Control.

   VMON (Vmon)
   Voltage Monitored value. It can be monitored either via Local or Remote Control.

   IMON (Imon)
   Current Monitored value. It can be monitored either via Local or Remote Control.

   TRIP (Trip)
   It is the maximum time an "overcurrent" is allowed to last (expressed in tenths of second). 
   If an "overcurrent" lasts for more than the programmed value, the System will react in the following ways:
      Trip =0..999: Ramp-down.
      It will cause the channel to "Trip": after an interval of time equal to the Trip value in tenths of second, 
      the output voltage will drop to zero at the rate specified by the Ramp-down parameter and the channel will be put in the Off state.
      Trip = 1000: Constant Current.
      The overcurrent may last indefinitely. If the Board has programmable current hardware protections, 
      the channel behaves like a current generator. It can be programmed either via Local or Remote Control. 

   POWER (Pw)
   It is the On/Off Status of the channel; by setting this parameter On the channel is On and the output drifts 
   from 0 to the programmed value at the programmed rate (if the interlock is not active and the CH OUT ENABLE switch is in the Enable position). 
   Via Terminal it is controlled by the Password Protection (see 'Password protection' ' and 'On/Off protection). 
   It can be programmed either via Local or Remote Control.
   
   PRIORITY ON/OFF (PrOn/PrOff)
   These parameters are active only via Terminal control in the Group operation. 
   The Priority On/Off of the channels in a Group allows to switch On or Off the channels with a determined sequence 
   in order to obtain the safest ON/OFF procedure.
      Priority On/Off = 0: The channel status is not affected by the Group ON/OFF command.
      Priority On/Off = 1..16: The channel status is affected by the Group ON/OFF command in such a way that channels with 
                               higher priority are switched ON/OFF before channels with lower priority. 

   POWER-ON ENABLE (Pon)
   This parameter controls the behavior of the channel at Power-On (On/Off).
   If this parameter is On, the channel reacts at Power-On, or after a Restart, restoring the same value of the Power parameter 
   at the time of the Power-Off or the Reset occurrence.
   All the channels with this parameter On are switched On following the sequence of priorities defined in GROUP00. 
   If the Power-On Status is Off, at Power-On or after a Reset the channel is Off regardless of its status before 
   the Power-Off or the Reset occurrence.
   It can be programmed either via Local or Remote Control.