Microchip Technology GPS-2700, Руководство пользователя

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GPS-2700 User’s Guide
DS50003016A-page 56
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2020 Microchip Technology Inc.
3.10.5 SERV:EFCS <float> [0.0, 500.0]
GPS-2700 with firmware revision 0.74 and later adds support for two different phase
loop time constant settings. See
Section 2.5 “Loop Parameter Adjustment” for
details of recommended loop time constant settings. Changing this parameter while
response of SERV:STAT? command is FAST will NOT change current operation of the
servo loop. This command will be effective only when SERV:STAT is NORMAL or
SERV:MODE is OFF.
It controls the Proportional part of the PID loop. Typical values are 0.6 to 6.0. Larger
values increase the loop control at the expense of increased noise while locked. Setting
this value too high can cause loop instabilities. This command has the following format:
SERV:EFCS <float> [0.0, 500.0]
The following command returns the current value for NORMAL EFC scale setting:
SERV:EFCS?
3.10.6 SERV:EFCD <int> [2, 4000]
GPS-2700 with firmware revision 0.74 and later adds support for two different phase
loop time constant settings. See
Section 2.5 “Loop Parameter Adjustment” for
details of recommended loop time constant settings. Changing this parameter while
response of SERV:STAT? command is FAST will NOT change current operation of the
servo loop. This command will be effective only when SERV:STAT is NORMAL or
SERV:MODE is OFF.
The command sets the Low Pass filter effectiveness of the DAC. Values from 5 to 50
are typically used. Larger values result in less noise at the expense of phase delay. This
command has the following format:
SERV:EFCD <int> [2, 4000]
The following command returns the current value for NORMAL EFC damping setting:
SERV:EFCD?
3.10.7 SERV:TEMPCO <float> [-4000.0, 4000.0]
This parameter is a coefficient that reflects the correlation between the temperature of
the CSAC versus the required frequency steering. Monitoring the tempco and aging
parameters provides a mechanism to track the health of the CSAC oscillator. Exces-
sively high values that appear from one day to the next could be an indicator of failure
on the board.
The CSAC has its own temperature compensation algorithm that is not compatible with
internal temperature compensation algorithm in GPS-2700 firmware. By default auto-
matic temperature compensation is disabled for GPS-2700 and default value is set to
0 which is equivalent to no additional temperature compensation applied.
Assigning a non-zero value to this parameter may result in frequency instability, and
assigned value will be stored in NV memory and remain unchanged. This command
has the following format:
SERV:TEMPCO <float> [-4000.0, 4000.0]
The following command returns the current value of the temperature compensation:
SERV:TEMPCO?