Intrinsically Safe Thermal Conductivity Dpm - Siemens Maxum II Service Manual

Thermal Conductivity Detector

2.1 Intrinsically Safe Thermal Conductivity DPM

2.1 Intrinsically Safe Thermal Conductivity DPM
Overview
Output signals from the Thermal Conductivity Detector (TCD) in the oven are wired to the
associated Detector Personality Module (DPM). The DPM is mounted inside the Electronics
Compartment (EC) on the floor of the compartment. The DPM digitizes the incoming analog
signal and then passes the data to the system controller via an I
then processed by the Embedded SNE software. Results can then be viewed on the
maintenance panel or the workstation.
GCP
Figure 2-1
The IS TCD DPM is an enclosed unit that is not field repairable. Opening the case voids the
safety protection of the device. Service is limited to replacement of the entire DPM.
Part Numbers
The IS TCD4 DPM is compatible with the MAXUM Airbath and Airless platforms for Intrinsically
Safe and non-Intrinsically Safe detectors. Where an Intrinsically Safe TCD is used, the safety
certification for the MAXUM Airbath and Airless only allow the IS TCD4 DPM. The IS TCD3
DPM is ONLY certified for use with an Intrinsically Safe detector in the Maxum Modular Oven
model. (Both IS TCD3 DPM and IS TCD4 DPM are certified for use in the Maxum Modular
Oven model). The Maxum Airbath and Airless models that use an Intrinsically Safe detector
are certified only when an IS TCD4 DPM is properly installed.
The IS TCD4 DPM (part number A5E43267455001) is installed in current analyzers. The IS
TCD3 DPM cannot be used as a replacement for the IS TCD4 DPM. See the note under the
Connections heading.
The IS TCD3 DPM (part number A5E02645923001) can be used as a replacement part for
earlier DPMs in Maxum I analyzers using an adapter, part number A5E34938550001. See the
publication
TC DPM in a Maxum or Maxum II Analyzer on the Siemens web site.
Intrinsic Safety
The intrinsic safety feature of this module was not used in early versions of the Maxum II Airless
and Airbath Oven model. The following two paragraphs apply only if this feature is used.
The TCD DPM in the Maxum II, as well as the actual detector controlled by the TCD, is
protected by intrinsic safety. Intrinsic safety is a method of protection where a circuit is designed
such that it will not create a spark or other condition capable of causing ignition of flammable
8
Network
SYSCON
Color
Touch
Display
Thermal Conductivity Detector Signal Path
IP-0034: Procedure to Replace Various TCD DPMs with Paired IS TCD DPM and
I 2 C I 2 C
PECM
C port. The resulting data is
2
IS-TCD Analog
TCD Beads
DPM
(thermistor)
(A/D)
Maxum Edition II Detectors
Service Manual, May 2018, A5E42019847001