DOC06501_Revision
F
ATS-6501 Users Guide
20
currently supported; users should contact Symmetricom about the possibility of utilizing other
clocks. The 5071A communications settings must be set to 9600 Baud, No Parity, 8 Data Bits,
and 1 Stop Bit (9600,N,8,1) and a null modem cable will be required.
WARNING:
Prior to setting the reference to external ensure the 10MHz signal from the
reference is connected to the 10MHz IN connector on the rear of the ATS-6501. If not, the ATS-
6501 outputs will not be within their specifications and it could take up to several hours for the
system to begin providing outputs within their specifications.
ATS-6501
5071
External reference
USB
To
Serial
Null Modem
Cable
USB
RS-232
(DTE)
10 MHz
Port 1/2
10 MHz In
Figure 6 External Frequency Reference
Current status can be determined using the
status oscillator:external
command.
ATS-6501>status oscillator:external
signal missing
10MHz reference signal is not present. Do NOT select the reference
type as External.
cannot communicate
10MHz reference signal is present but the system is unable to
communicate with the 5071A
locked
10MHz reference signal is present and the system is able to
communicate with the 5071A
unknown
10MHz reference signal is present. The system will not attempt to
communicate with the external reference.
Note:
Make sure the USB-to-Serial Converter (OP-002) is installed on one of the two USB ports
when the system is powered on. If not, power the system down, plug the cable in and re-apply
power. The USB/Serial Cables are programmed to communicate with an external reference (OP-
002) or to provide users access to the command port (OP-001). These cables are
NOT
interchangeable.
To set the type of reference use the
reference_type
command. If users are operating with
a Symmetricom 5071A and they will set the system up so the ATS-6501 is
communicating with the 5071A select
hp5071A
, if not select
cesium
.
ATS-6501>reference_type hp5071a
OK
Caution:
If the system is unable to communicate with the external reference and the
reference_type
is hp5071A the Alarm light will come on and the Osc Lock light will go
out and remain this way after you switch to the external reference. Make sure you select
the proper
reference_type
before switching to external.
To set the reference to external use the
reference
command via the command port.
ATS-6501>reference external
OK