Re quested data is re turned in the same for mat as with GPIB, but with a pre -
ced ing 'R' and a ter mi nat ing new line char ac ter. SRQs are avail able, and are
out put as SRQ mes sage 'S' fol lowed by a ter mi nat ing new line char ac ter. When
the SRQ mes sage has been re ceived, an "!SPL" com mand (equiv a lent to the
GPIB se rial poll) can be is sued. The power me ter will re spond with the se rial
poll data mes sage which is a sin gle char ac ter pre ceded by 'P' and ter mi nated by
a new line char ac ter.
A de vice clear mes sage
!DCL can be sent to clear the power me ter in put and
out put mes sage queues, and ter mi nate any GPIB or se rial ac tions pend ing.
At power on, fac tory re set, in re sponse to the MODINIT com mand, and af ter
the INIT key in the mo dem menu is pressed, the fol low ing se quences will be
out put:
1. +++ath\r\r
2. at&h1&r2x4v1q0f1s0=1e0\r\r
There will be a de lay be tween the two se quences.
These se quences will initialize an at tached Hayes-compatible mo dem. This is
the only type of mo dem sup ported.
5-10 RS232 MODEM
SUPPORT
The ML2400A Se ries Power Me ter can be op er ated re motely through a mo dem
con nected to the rear panel se rial con nec tor (See Chap ter 3, Con nec tors, for
the lo ca tion of the se rial con nec tor) us ing the GPIB/RS232 com mand set. The
menu selection
Sys tem|Rear panel|RS232|MODE must be set to EXT COMMS .
To ini ti ate com mu ni ca tions with the power me ter from a re mote com puter,
com mu ni ca tions must be es tab lished be tween the two mo dems. Once this is
done, the mo dems be come trans par ent to the user, and GPIB/RS232 com -
mands can be en tered as if the power me ter is con nected di rectly to the re mote
com puter.
The power me ter can also be con fig ured to au to mat i cally dial a spec i fied num -
ber if one or more pre de ter mined er ror con di tions are met.
When an in stru ment state change oc curs that ini ti ates an AUTODIAL se -
quence, the power me ter will send an es cape se quence "+++" to the mo dem. It
will then out put com mands to de ter mine if there is a mo dem con nected and, if
there is, whether it is con nected through to an other mo dem. If a mo dem is
found and it is not con nected to a re mote mo dem, the power me ter will dial the
num ber spec i fied in the "phone num ber" field. When the con nec tion to the re -
mote com puter is es tab lished, the power me ter will send the se rial SRQ
mes sage.
When an autodial se quence is ini ti ated, dif fer ent sets of char ac ters will be seen
on the re mote PC de pend ing on what is con nected to the power me ter se rial
port.
5-6 ML2400A OM
RS232 MODEM SUPPORT PROCEDURES
NOTE
Se rial in ter face re mote
op era tion is not avail -
able when the
ML2400A Se ries
Power Me ter is op er at -
ing from the in ter nal
bat tery.
NOTE
It is rec om mended that
there is only one se rial
com mand in each com -
mand string. Ter mi nate
each com mand with a
newline char ac ter.
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