Loop Tests; Data Transfer; Esd Protection; Ground Safety Connection - HP M2350A Service Manual

Understanding the Computer Module
The Function Cards
Loop Tests
An internal loop test checks HSCX operation. The HDLC drivers are tested by an HSCX
external
loop, which can be opened or closed by resetting/setting the test loop register.
Data Transfer
The HDLC Interface communicates with the connected devices in a Master-Slave configuration,
with the HDLC Interface as Master.
Commands and data from the MPB are received by the CPU on the HDLC Interface. The CPU
interprets the commands and rearranges the data into the format required by the HSCX and
STRIP protocol. It then loads the data into the HSCX to be transmitted to the external HDLC
devices.
Data which is received from the devices is reformatted by the CPU and transmitted via the
MPB.
The CPU can also be commanded to poll the connected devices automatically every
32ms,
for
synchronization.
ESD Protection
Caution
The HDLC connector shields all ESDs
when no
cable is connected to the port
on the HDLC link. However, ESDs into the
UnCOMeCted
end of an HDLC cable
which is connected to the HDLC Interface on the computer module will result
in driver damage. Always disconnect
the
HDLC cable at the computer module
end when no other equipment is attached to the cable.
Grouud Safety Connection
Warning
There is no signal ground connection on the HDLC cable to STRIP devices;
the cable shield is only connected at one end of the cable. For this reason,
the signal ground and safety ground in each HDLC device must be tied
together. Additionally, there must be a connection between the safety
ground of all devices and the power cord safety ground or additional
grounding cables.
n
Provides an interface to real-time wave recorders.
n
Performs internal tests to check the operation of the controller and drivers.
n
Controls a maximum of two devices in daisy chain.
n
Receives commands and data via the MPB.
n
Formats the data to HSCX and STRIP protocol, then transmits to connected devices.
n
Receives data from devices, which it then transmits over MPB.
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