Spellman High Voltage Electronics Corporation One Commerce Park,
Valhalla, NY 10595, (914) 686-3600, Fax: (914) 686-2870
SECTION
III
GPIB
OPERATION
CAUTION –
THE UNIT BEING CONTROLLED BT THE 200-C488 CAN STORE
HAZARDOUS VOLTAGE. COMPLETELY DISCHARGE HIGH VOLTAGE AT
REAR PANEL GROUND TERMINAL BEFORE ATTEMPTING REMOVAL OF
THE HIGH VOLTAGE CABLE.
3.1
GPIB PROTOCOL
The 200-C488 implements the following GPIB Functions:
SH1
Source Handshake
AH1
Acceptor Handshake
T1
Basic Talker & Serial Poll
L1
Basic Listener
SR1
Service Request
DC1
Device Clear
DT1
Device Trigger
Using these GPIB functions, the GPIB controller may send ASCII command strings to control and monitor
the high voltage power supply.
3.1.1
DATA TRANSFER FUNCTIONS – SH1, AH1, T1, L1
SH1, AH1, T1, and L are data transfer functions, and normally transparent to the User. These functions
permit the communication between the GPIB controller and the Model 200-c488 interface.
3.1.2
SERVICE REQUEST FUNCTIONS – SR1
SR1 contains two sub-functions; Service Request and Serial Poll. The service request is the mechanism by
which the 200-C488 may interrupt the GPIB controller and the serial poll is how the GPIB controller may
read the status of the 200-C488.
3.1.2.1 SERVICE REQUEST
There are two conditions that will cause the 200-C488 to generate a service request; at power-on and during
user programmed overload detection. The meaning of the serial poll status byte that is read depends on the
condition that caused the service request. The power –on mode is true when the 200-C488 is first turned on
and before the GPIB controller sends a command to the interface. The overload detect mode is after the
GPIB control has sent its first command to the interface. Any service request may be ignored without
affecting operation of the interface or power supply.
3.1.2.2
SERIAL POLL
When the GPIOB controller executes a serial poll, the 200-C488 sends it one byte of status. As mentioned
above, the decoding of the status byte is dependent on when it is read. The FIGURE 3.1 below shows the
decoding of the power-on status byte, and FIGURE 3.2 shows the decoding of the ‘normal operation” (not
the power-on) status byte.
Artisan Technology Group - Quality Instrumentation ... Guaranteed | (888) 88-SOURCE | www.artisantg.com
