Firmware version 4.15 solves a
problem in version 4.14 where the 875CR measurement may randomly become
unstable for 2 second durations. The instability may amount to as much as
full scale error in absolute, temperature, or final measurement in some instances.
These instabilities when they occur affect the analog outputs, and may
cause the 875CR alarms to trigger falsely.
You may view your current firmware
version number under the 875CR "STATUS" mode as described in MI 611- 222, Table 7.
If you currently have an 875CR
running version 4.14, Foxboro strongly recommends that you upgrade to version
4.15 (or later).
Version 4.15 may be installed using
the 875 Upgrade Utility, part number BS811FN available from the Foxboro
Company - Invensys Process Systems. If you already have the upgrade
utility, then you may download file CR0415.ZIP from the internet, unzip it, and
install it using your existing upgrade utility program. For step by step
instructions, refer to MI 611-228.
In lieu of using this field upgrade
procedure you may elect to return your 875CR to the factory for upgrade.
To arrange for factory upgrade contact Foxboro’s
If you currently have an
875CR running a firmware version starting with 4, but lower than 4.14, then
your 875CR is not subject to the measurement instability, and no action is
required. However, you may choose to load version 4.15 to obtain the
latest feature set including enhanced immunity to
electro-static discharge (ESD).