3-3
3.2
Back Panel Connections
Figure 3. Rear Panel
AC Power Mains Input and Fuse Compartment:
The customer connects the power cord to the AC Power Input. As a safety
precaution, the power cord cannot be connected if the fuse compartment is open.
Refer to Section 5.3 for information on fuse replacement.
Reference Probe Connection:
The reference probe enables the user to monitor the target plate temperature
with an external instrument. A “K” type thermocouple reference output is
provided.
RS232 Communications Port:
The female DB-9 port allows the customer to make a 3-wire RS232 interface with
the BB-4A. A detailed description of this port is described in Section 4.
3.3
Thermal Reset Switch
In the event that the target plate temperature and/or ambient temperature
exceeds the acceptable limit, this reset switch will pop open. The controller will
appear to be demanding a temperature increase but the target plate temperature
will not rise. Let the unit cool down, completely. Press the switch located on the
right side of the unit, behind the carry handle until a click is heard. If this has no
effect refer to the troubleshooting section.
3.4
Changing the Temperature Setpoint
The layout of the front panel is shown in Figure 2. The BB-4A incorporates a PID
digital setpoint controller. The upper display indicates the blackbody target plate
temperature known as (PV) Process Variable, while the lower display indicates
the programmed setpoint known as (SV) Setpoint Variable. Making changes to
the setpoint, units of measure (°F/°C) and communication settings (BAUD, etc.)
BB-4A Blackbody Calibrator
3
AC MAINS POWER INPUT
AND FUSE COMPARTMENT
TC REFERENCE
PROBE CONNECTION
FAN
FUSE
RS-232 COMMUNICATIONS PORT