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C. IEEE -488 Interface Option for Filter Controllers
The IEEE-488 interface option allows control of ARC Filter Control unit from the IEEE-488 bus. All
of the commands and status requests described in Section B - Operation with RS-232 Computer or
Terminal - are available through the IEEE-488 option. The following standard interface functions are
provided:
SH1, AH1, T2, L2, SR1, RL1 (NOTE: The local lockout command
is not accepted but the front panel is automatically locked out when
in remote), PP0, DC0, C0
The GPIB device identifier or address may be sent by dip switches on the interface board. The
switches are accessible on the bottom of the control unit by removing screws to the access plate.
The factory set device address is 10. The command ?ID will report back the current device address.
The following table shows the function of each switch position:
S1-1 on = address 1 decimal, off = address 0
S1-2 on = address 2 decimal, off = address 0
S1-3 on = address 4 decimal, off = address 0
S1-4 on = address 8 decimal, off = address 0
S1-5 on = address 16 decimal, off = address 0
S1-6 factory set to on
S1-7 factory set to off
S1-8 factory set to off
S1-9 factory set to on
S1-10 factory set to on
The last byte of each command string to the Filter Control unit must be a <CR> (hex OD). The end
message (EOI line) is accepted but not required. When the SpectraPro™ is a talker, each string
sent back to the controller ends with a <LF> (hex 0A) with the EOI line set.
The Filter Control unit will issue a service request based upon the contents of the service request
mask which is set by the SET-MASK command and read by the ?MASK command. The bits of the
mask are as follows:
bit 0 previously sent command is complete
bit 1 previous command generated an error
bit 7 previous command generated a response which is
now ready to be sent
The default value for the service request mask is ø, therefore, no service request is generated. To
change the mask to generate a service request on error or response ready, for example, issue the
command 130 SET-MASK <CR>. This new value is reset to the default value on reset or power-up.
The Filter Control unit responds to a serial poll with a status byte that uses the same bit pattern as
the service request mask shown above.
The following page is a Basic program listing illustrating the use of the filter controllers from a
National Instruments PC-IIA GPIB Controller.
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